U.S. patent application number 13/299448 was filed with the patent office on 2013-01-10 for metal-enolate precursors for depositing metal-containing films.
This patent application is currently assigned to Air Products and Chemicals, Inc.. Invention is credited to Xinjian Lei, John Anthony Thomas Norman.
Application Number | 20130011579 13/299448 |
Document ID | / |
Family ID | 45093509 |
Filed Date | 2013-01-10 |
United States Patent
Application |
20130011579 |
Kind Code |
A1 |
Norman; John Anthony Thomas ;
et al. |
January 10, 2013 |
Metal-Enolate Precursors For Depositing Metal-Containing Films
Abstract
Organometallic compounds suitable for use as vapor phase
deposition precursors for metal-containing films are provided.
Methods of depositing metal-containing films using certain
organometallic precursors are also provided. Such metal-containing
films are particularly useful in the manufacture of electronic
devices.
Inventors: |
Norman; John Anthony Thomas;
(Encinitas, CA) ; Lei; Xinjian; (Vista,
CA) |
Assignee: |
Air Products and Chemicals,
Inc.
Allentown
PA
|
Family ID: |
45093509 |
Appl. No.: |
13/299448 |
Filed: |
November 18, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61418055 |
Nov 30, 2010 |
|
|
|
Current U.S.
Class: |
427/569 ;
427/255.28; 556/54 |
Current CPC
Class: |
C23C 16/405 20130101;
C23C 16/45553 20130101; C07F 17/00 20130101; C23C 16/18
20130101 |
Class at
Publication: |
427/569 ; 556/54;
427/255.28 |
International
Class: |
C07F 7/28 20060101
C07F007/28; C23C 16/455 20060101 C23C016/455 |
Claims
1. A metal-containing precursor comprising an enolate ligand
represented by the following Formula 1: ##STR00018## wherein, M is
a metal with an oxidation state of (n), from +2 to +6, selected
from the Lanthanides or Group 3 to Group 16, of the Periodic Table;
R.sup.1, R.sup.2 and R.sup.3 are independently H or C.sub.1-C.sub.6
selected from the group consisting of: methyl, ethyl, propyl,
iso-propyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec
pentyl, hexyl, sec-hexyl, tert-butyl tert-amyl, and valeraldyl; (L)
is an anionic ligand or a mixture of anionic ligands selected from
the group consisting of: alkyl substituted enolate, alkoxy, alkyl
amino, dialkylamino, diketonate, ketoiminate, diiminate,
guanidinate, amidinate, cyclopentadienyl, alkyl substituted
cyclopentadienyl, alkoxy substituted cyclopentadienyl, amino
substituted cyclopentadienyl, pyrrolyl, alkyl substituted pyrrolyl,
alkoxy substituted pyrrolyl, amino substituted pyrrolyl;
imidazolate, alkyl substituted imidazolate, alkoxy substituted
imidazolate, amino substituted imidazoolate, alkoxy substituted
imidazolate, pyrazole, alkyl substituted pyrazole, alkoxy
substituted pyrazolate, and alkoxy substituted pyrazolate; (L) can
also be a dienolate dianion; (Z) is a neutral coordinating ligand
selected from the group consisting of an alkylamine,
polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1 to 4; (x)=1 to 6; and R.sup.2 can form a cyclic
structure with M.
2. The precursor of claim 1 comprising
bis(2,2,5,5-tetramethylhex-3-en-3-olato)hexa(ethoxy)di-titanium.
3. The precursor of claim 1 comprising
bis(2,2,5,5-tetramethylhex-3-en-3-olato)(bis(iso-propoxy)titanium.
4. The precursor of claim 1 comprising
tris(2,2,5,5-tetramethylhex-3-en-3-olato)(dimethylamido)titanium.
5. The precursor of claim 1 comprising a compound from Formula 1,
wherein (L) is a C.sub.1-C.sub.10 alkoxy group, as represented by
structure A1. ##STR00019## wherein, M is a metal with an oxidation
state of (n) ranging from +2 to +6, selected from the Lanthanides
or Group 3 to Group 16, of the Periodic Table; R.sup.1, R.sup.2,
and R.sup.3 are independently H or C.sub.1-C.sub.6 selected from
the group consisting of: methyl, ethyl, propyl, iso-propyl, butyl,
isobutyl, sec-butyl, pentyl, isopentyl, sec pentyl, hexyl,
sec-hexyl, tert-butyl, tert-amyl, and valeraldyl; R.sup.4 is
selected from the group methyl, ethyl, propyl, iso-propyl, butyl,
isobutyl, sec-butyl, pentyl, isopentyl, sec pentyl, hexyl,
sec-hexyl, tert-butyl tert-amyl, and valeraldyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1-4; (x)=1 to 6.
6. The precursor of claim 1 comprising a compound from Formula 1,
wherein (L) is an alkoxy anion, as represented by Structure A2:
##STR00020## wherein, M is a metal with an oxidation state of (n)
ranging from +2 to +6, selected from the Lanthanides or Group 3 to
Group 16, of the Periodic Table; R.sup.1, R.sup.2 and R.sup.3 are
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec pentyl, hexyl, sec-hexyl,
tert-butyl and tert-amyl, and valeraldyl; R.sup.4 is selected from
the group consisting of methyl, ethyl, propyl, iso-propyl, butyl,
isobutyl, sec-butyl, pentyl, isopentyl, sec pentyl, hexyl,
sec-hexyl, tert-butyl, tert-amyl, and valeraldyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1-4; (x)=1 to 6.
7. The precursor of claim 1 comprising a compound from Formula 1,
wherein (L) is a cyclopentadienyl anion, as represented by
Structure B ##STR00021## wherein, M is a metal with an oxidation
state of (n) ranging from +2 to +6, selected from the Lanthanides
or Group 3 to Group 16, of the Periodic Table; R.sup.1, R.sup.2,
R.sup.3 and R.sup.5 are independently H or C.sub.1-C.sub.6 selected
from the group consisting of: methyl, ethyl, propyl, iso-propyl,
butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec pentyl, hexyl,
sec-hexyl, tert-butyl, tert-amyl, and valeraldyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1-4; (x)=1 to 6; (m)=1 to 5.
8. The precursor of claim 1 comprising a compound from Formula 1,
wherein (L) is a pyrrolyl anion, as represented by Structure C:
##STR00022## wherein, M is a metal with an oxidation state of (n)
ranging from +2 to +6, selected from the Lanthanides or Group 3 to
Group 16, of the Periodic Table; R.sup.1, R.sup.2, R.sup.3 and
R.sup.6 are independently H or C.sub.1-C.sub.6 selected from the
group consisting of: methyl, ethyl, propyl, iso-propyl, butyl,
isobutyl, sec-butyl, pentyl, isopentyl, sec pentyl, hexyl,
sec-hexyl, tert-butyl, tert-amyl, and valeraldyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1 to 4; (x)=1 to 6; (p)=1 to 4.
9. The precursor of claim 1 comprising a compound from Formula 1,
wherein (L) is an imidazolate anion, as represented by Structure D:
##STR00023## wherein, M is a metal with an oxidation state of (n)
ranging from +2 to +6, selected from the Lanthanides or Group 3 to
Group 16, of the Periodic Table; R.sup.1, R.sup.2, R.sup.3 and Ware
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1 to 4; (x)=1 to 6; (q)=1, 2 or 3.
10. The precursor of claim 1 comprising a compound from Formula 1,
wherein (L) is a pyrazolate anion, as represented by Structure E:
##STR00024## wherein M is a metal with an oxidation state of (n)
ranging from +2 to +6 selected from the Lanthanides or Group 3 to
Group 16 of the Periodic Table; (n) ranges from +2 to +6; R.sup.1,
R.sup.2, R.sup.3 and R.sup.8 are independently H or C.sub.1-C.sub.6
selected from the group consisting of: methyl, ethyl, propyl,
iso-propyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec
pentyl, hexyl, sec-hexyl, tert-butyl tert-amyl, valeraldyl and
tert-amyl; (Z) is a neutral coordinating ligand selected from the
group consisting of an alkyl amine, polyalkylamine, ether,
polyether, imidazole, pyridine, alkyl substituted pyridine,
pyrimidine, alkyl substituted pyrimidine, and oxazole; (x)=1 to 4;
r=1, 2 or 3; (y)=1 to 4.
11. The precursor of claim 1 comprising a compound represented by
Formula 2: ##STR00025## wherein M is a metal with an oxidation
state of (n) ranging from +2 to +6 selected from the Lanthanides or
Group 3 to Group 16 of the Periodic Table; R.sup.9, R.sup.10,
R.sup.11 and R.sup.12 are independently H or C.sub.1-C.sub.6
selected from the group consisting of: methyl, ethyl, propyl,
iso-propyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec
pentyl, hexyl, sec-hexyl, tert-butyl, tert-amyl, valeraldyl; (L)
represents an anion or anions selected from the group consisting
of: alkyl substituted enolate anion, alkoxy, guanidinate,
amidinate, dialkylamide, diketonate, ketoiminate, diiminate,
cyclopentadienyl, alkyl substituted cyclopentadienyl,
alkoxysubstituted cyclopentadienyl, aminosubsitituted
cyclopentadienyl, pyrrolyl, alkyl substituted pyrrolyl,
alkoxysubstituted pyrrolyl, aminosubsitituted pyrrolyl, alkyl
substituted imidazolate, and alkoxysubstituted imidazolate; (Z) is
a neutral coordinating ligand selected from the group consisting of
an alkyl amine, polyalkylamine, ether, polyether, imidazole,
pyridine, alkyl substituted pyridine, pyrimidine, alkyl substituted
pyrimidine, and oxazole; (x)=1 to 3; (y)=1 to 4.
12. The precursor of claim 11 comprising
bis(2,2,7,7-tetramethylocta-3,5-dien-3,6-diolato)bis(dimethylamino)titani-
um.
13. The precursor of claim 1 comprising is a compound represented
by Formula 3: ##STR00026## wherein M is a metal with an oxidation
state of (n) ranging from +2 to +6 selected from the Lanthanides or
Group 3 to Group 16 of the Periodic Table; R.sup.13, R.sup.14 and
R.sup.15 are independently H or C.sub.1-C.sub.6 selected from the
group consisting of: methyl, ethyl, propyl, iso-propyl, butyl,
isobutyl, sec-butyl, pentyl, isopentyl, sec pentyl, hexyl,
sec-hexyl, tert-butyl, tert-amyl, and valeraldyl; (L) represents an
anion or anions selected from the group consisting of: alkyl
substituted enolate anion, alkoxy, guanidinate, amidinate,
dialkylamide, diketonate, ketoiminate, diiminate, cyclopentadienyl,
alkyl substituted cyclopentadienyl, alkoxysubstituted
cyclopentadienyl, aminosubsitituted cyclopentadienyl, pyrrolyl,
alkyl substituted pyrrolyl, alkoxysubstituted pyrrolyl,
aminosubsitituted pyrrolyl; alkyl substituted imidazolate, and
alkoxysubstituted imidazolate; (Z) is a neutral coordinating ligand
selected from the group consisting of an alkyl amine,
polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (x)=1 to 3; (y)=1 to 4.
14. The precursor of claim 1 comprising a compound represented by
Structure 4: ##STR00027## wherein M is a metal with an oxidation
state of (n) ranging from +2 to +6 selected from the Lanthanides or
Group 3 to Group 16 of the Periodic Table; R.sup.16, R.sup.17 are
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; (L) represents an anion or
anions selected from the group consisting of: alkyl substituted
enolate anion, alkoxy, guanidinate, amidinate, dialkylamide,
diketonate, ketoiminate, diiminate, cyclopentadienyl, alkyl
substituted cyclopentadienyl, alkoxysubstituted cyclopentadienyl,
aminosubsitituted cyclopentadienyl, pyrrolyl, alkyl substituted
pyrrolyl, alkoxysubstituted pyrrolyl, aminosubsitituted pyrrolyl;
alkyl substituted imidazolate, and alkoxysubstituted imidazolate;
(Z) is a neutral coordinating ligand selected from the group
consisting of an alkyl amine, polyalkylamine, ether, polyether,
imidazole, pyridine, alkyl substituted pyridine, pyrimidine, alkyl
substituted pyrimidine, and oxazole; (x)=1 to 3; (y)=1 to 4.
15. The precursor of claim 1 comprising a compound represented by
Formula 4: ##STR00028## wherein M is a metal with an oxidation
state of (n) ranging from +2 to +6 selected from the Lanthanides or
Group 3 to Group 16 of the Periodic Table; R.sup.18, R.sup.19
R.sup.20 and R.sup.21 are independently H or C.sub.1-C.sub.6
selected from the group consisting of: methyl, ethyl, propyl,
iso-propyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec
pentyl, hexyl, sec-hexyl, tert-butyl, tert-amyl, and valeraldyl;
(L) represents an anion or anions selected from the group
consisting of: alkyl substituted enolate anion, alkoxy,
guanidinate, amidinate, dialkylamide, diketonate, ketoiminate,
diiminate, cyclopentadienyl, alkyl substituted cyclopentadienyl,
alkoxysubstituted cyclopentadienyl, aminosubsitituted
cyclopentadienyl, pyrrolyl, alkyl substituted pyrrolyl,
alkoxysubstituted pyrrolyl, aminosubsitituted pyrrolyl; alkyl
substituted imidazolate, and alkoxysubstituted imidazolate; (Z) is
a neutral coordinating ligand selected from the group consisting of
an alkyl amine, polyalkylamine, ether, polyether, imidazole,
pyridine, alkyl substituted pyridine, pyrimidine, alkyl substituted
pyrimidine, and oxazole; (x)=1 to 3; (y)=1 to 4.
16. The compound of claim 1 selected from the group consisting of:
methylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)titanium,
methylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)zirconium,
methylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)hafnium,
ethylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)titanium,
ethylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)zirconium,
ethylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)hafnium,
methylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)titanium,
methylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)zirconium,
methylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)hafnium,
ethylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)titanium,
ethylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)zirconium,
ethylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)hafnium,
methylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)titanium,
methylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)zirconium,
methylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)hafnium,
ethylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)titanium,
ethylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)zirconium,
and
ethylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)hafnium.
17. A method for forming a metal-containing film by a vapor
deposition, the method comprises the steps of: a. introducing a
metal-containing precursor of claim 1 in a vapor state into a
reaction chamber and chemisorbing the metal-containing precursor
onto a substrate which is heated; b. purging away the unreacted
metal-containing precursor; c. introducing an oxygen source onto
the heated substrate to react with the sorbed metal-containing
precursor; and d. purging away the unreacted oxygen source.
18. A method for forming a metal-containing films using the
precursors of claim 1.
19. A method for forming a metal containing film using the
precursors of claim 1 in a CVD technique.
20. A method for forming a metal containing film using the
precursors of claim 1 in a PECVD technique.
21. A method for forming a metal containing film using the
precursors of claim 1 in an AVD technique.
22. A method for forming a metal-containing film by an ALD method,
the method comprises the steps of: a. introducing a
metal-containing precursor of claim 1 in a vapor state into a
reaction chamber and chemisorbing the metal-containing precursor
onto a heated substrate; b. purging away the unreacted
metal-containing precursor; c. introducing an oxidizing source
selected from the group consisting of oxygen, ozone, nitrous oxide
or water onto the heated substrate to react with the adsorbed
metal-containing precursor; and, d. purging away the unreacted
oxidizing source; and, this sequence of cycles is then repeated to
build up the metal oxide film to a desired thickness.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present patent application claims the benefit of prior
U.S. Provisional Patent Application Ser. No. 61/418,055 filed Nov.
30, 2010.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to the field of
organometallic compounds. In particular, the present invention
relates to the certain organometallic compounds suitable for use in
vapor deposition processes such as, but not limited to, atomic
layer deposition (ALD) or cyclic chemical vapor deposition (CCVD),
that may be used to form, for example, a gate dielectric or
capacitor dielectric film in a semiconductor device.
[0003] With each generation of metal oxide semiconductor (MOS)
integrated circuit (IC), the device dimensions have been
continuously scaled down to provide for high-density and
high-performance such as high speed and low power consumption
requirements. Unfortunately, field effect semiconductor devices
produce an output signal that is proportional to the width of the
channel, such that scaling reduces their output. This effect has
generally been compensated for by decreasing the thickness of gate
dielectric, thus bring the gate in closer proximity to the channel
and enhancing the field effect which thereby increasing the drive
current. Therefore, it has become increasingly important to provide
extremely thin reliable and low-defect gate dielectrics for
improving device performance.
[0004] For decades, a thermal silicon oxide, SiO.sub.2, has been
mainly used as a gate dielectric because it is stable with the
underlying silicon substrate and its fabrication process is
relatively simple. However, because the silicon oxide gate
dielectric has a relatively low dielectric constant (k), 3.9,
further scaling down of silicon oxide gate dielectric thickness has
become more and more difficult, especially due to gate-to-channel
leakage current through the thin silicon oxide gate dielectric.
[0005] This leads to consideration of alternative dielectric
materials that can be formed in a thicker layer than silicon oxide
but still produce the same or better device performance. This
performance can be expressed as "equivalent oxide thickness (EOT)".
Although the alternative dielectric material layer may be thicker
than a comparative silicon oxide layer, it has the equivalent
effect of a much thinner layer of silicon oxide layer.
[0006] To this end, high-k metal oxide materials have been proposed
as the alternative dielectric materials for gate or capacitor
dielectrics. Metal-containing precursors may also be used by
themselves or combined with other metal-containing precursors, such
as, for example, Pb(Zr,Ti)O.sub.3 or (Ba,Si)(Zr,Ti)O.sub.3, to make
high dielectric constant and/or ferroelectric oxide thin films.
Because the dielectric constant of metal oxide materials can be
made greater than that of the silicon oxide, a thicker metal oxide
layer having a similar EOT can be deposited. As a result, the
semiconductor industry requires metal-containing precursors, such
as, for example, titanium-containing, zirconium-containing, and
hafnium-containing precursors and combinations thereof, to be able
to deposit metal-containing films such as, but not limited to,
oxide, nitride, silicate or combinations thereof on substrates such
as metal nitride or silicon.
[0007] Unfortunately, the use of high-k metal oxide materials
presents several problems when using traditional substrate
materials such as silicon. The silicon can react with the high-k
metal oxide or be oxidized during deposition of the high-k metal
oxide or subsequent thermal processes, thereby forming an interface
layer of silicon oxide. This increases the equivalent oxide
thickness, thereby degrading device performance. Further, an
interface trap density between the high-k metal oxide layer and the
silicon substrate is increased. Thus, the channel mobility of the
carriers is reduced. This reduces the on/off current ratio of the
MOS transistor, thereby degrading its switching characteristics.
Also, the high-k metal oxide layer such as, for example, a hafnium
oxide (HfO.sub.2) layer or a zirconium oxide (ZrO.sub.2) layer has
a relatively low crystallization temperature and is thermally
unstable. Thus, the metal oxide layer can be easily crystallized
during a subsequent thermal annealing process used to distribute
the n and p type dopants previously injected into source/drain
regions of the device. Crystallization can lead to the formation of
grain boundaries in the metal oxide layer through which current can
pass thereby degrading the performance of the dielectric oxide as
an insulator. Crystallization can also lead an increase in the
surface roughness of the metal oxide layer which can also lead to
current leakage and dielectric deterioration. Further, the
crystallization of the high-k metal oxide layer can also
undesirably affect subsequent lithographic alignment processes, due
to irregular reflection of the light by the rough surfaces.
[0008] In addition to minimizing side reactions with the substrate
upon which the metal-containing precursor is deposited, it is also
desirable that the metal-containing precursor is thermally stable,
and preferably in liquid or low melting solid form. Group
4-containing metal films, for example, are typically deposited
using a vapor deposition (e.g., chemical vapor deposition and/or
atomic layer deposition) process. It is desirable that these
precursors are thermally stable during vapor delivery in order to
avoid premature decomposition of the precursor before it reaches
the vapor deposition chamber during processing. Premature
decomposition of the precursor not only results in undesirable
accumulation of side products that will clog fluid flow conduits of
the deposition apparatus, but also may cause undesirable variations
in composition of the deposited gate dielectric, high dielectric
constant and/or ferroelectric metal oxide thin film.
[0009] Although metal enolate species have been reported as
intermediates and catalytic chemical species used organic synthesis
(Tetrahedron Lett. FIELD Full Journal Title: Tetrahedron Letters
22(47): 4691-4), they have not be isolated as low melting, cleanly
evaporating and thermally stable molecules for use in thin film
deposition processes, as those described below.
[0010] Other prior art includes; US2007/0248754A1, U.S. Ser. No.
11/945,678 filed on Nov. 27, 2007, Applicants' co-pending
application U.S. Ser. No. 12/266,806 which was filed on Nov. 11,
2008; Applicants' patents U.S. Pat. No. 7,691,984, and U.S. Pat.
No. 7,723,493.
[0011] Accordingly, there is a need to develop metal-containing
precursors, preferably liquid Group 4 precursors, which exhibit at
least one of the following properties: high thermal stability, high
chemical reactivity and low melting points.
BRIEF SUMMARY OF THE INVENTION
[0012] Described herein are enolate based metal-containing
precursors and deposition processes using these precursors for
fabricating conformal metal containing films on substrates such as
silicon, metal nitride and other metal layers by Atomic Layer
Deposition (ALD), Plasma Enhanced Atomic Layer Deposition (PEALD),
Atomic Vapor Deposition (AVD), Chemical Vapor Deposition (CVD) and
Plasma Enhanced Chemical Vapor Deposition (PECVD).
[0013] These metal enolates are shown to be low melting solids,
that evaporate cleanly to give low residues in Thermo Gravimetric
Analysis (TGA) experiments and are, hence, excellent candidate
precursor for these deposition techniques. In the TGA technique a
sample of precursor is weighed in a microbalance while being
subjected to steadily increasing temperature under a steady flow of
nitrogen. Clean evaporation with low involatile residue in the
hallmark of a good precursor. The residue is preferable <10 wt
%, preferable <5%, preferably <2%.
[0014] While not wishing to be bound by theory, it is believed that
the enolate or dienolate species of this disclosure are optimally
substituted with alkyl group in a manner which minimizes
inter-molecular association, to permit clean vaporization. The
alkyl group substitution pattern also can lower the melting point
of the metal complex and provide for high reaction rates under ALD
or CVD conditions.
[0015] This invention also discloses the synthesis of these enolate
and dienolate precursors, and their use as ALD or CVD precursors.
In addition, while not wishing to be bound by theory, it is
believed that the highly novel and rare metal dienolate compounds
of this disclosure have additional uses and applications,
including, but not limited to, catalysts and as synthetic
intermediates in chemical synthesis.
[0016] The metal-containing precursors of the present invention
comprise an enolate ligand and are represented by the following
Formula 1:
##STR00001##
[0017] wherein, M is a metal with an oxidation state of (n), from
+2 to +6, selected from the Lanthanides or Group 3 to Group 16, of
the Periodic Table; R.sup.1, R.sup.2 and R.sup.3 are independently
H or C.sub.1-C.sub.8 selected from the group consisting of: methyl,
ethyl, propyl, iso-propyl, butyl, isobutyl, sec-butyl, pentyl,
isopentyl, sec-pentyl, hexyl, sec-hexyl, tert-butyl, tert-amyl, and
valeraldyl; (L) is an anionic ligand or a mixture of anionic
ligands selected from the group consisting of: alkyl substituted
enolate, alkoxy, alkyl amino, dialkylamino, diketonate,
ketoiminate, diiminate, guanidinate, amidinate, cyclopentadienyl,
alkyl substituted cyclopentadienyl, alkoxy substituted
cyclopentadienyl, amino substituted cyclopentadienyl, pyrrolyl,
alkyl substituted pyrrolyl, alkoxy substituted pyrrolyl, amino
substituted pyrrolyl; imidazolate, alkyl substituted imidazolate,
alkoxy substituted imidazolate, amino substituted imidazoolate,
alkoxy substituted imidazolate, pyrazole, alkyl substituted
pyrazole, alkoxy substituted pyrazolate, and alkoxy substituted
pyrazolate; (L) can also be a dienolate dianion. (Z) is a neutral
coordinating ligand, such as an alkylamine, polyalkylamine, ether,
polyether, imidazole, pyridine, alkyl substituted pyridine,
pyrimidine, alkyl substituted pyrimidine, oxazole, (y)=1 to 4,
(x)=1 to 6; and R.sup.2 can form a cyclic structure with M.
[0018] In yet another aspect, the present invention is a compound
from Formula 1, wherein (L) is a C.sub.1-C.sub.10 alkoxy group, as
represented by structure A1.
##STR00002##
[0019] wherein, M is a metal with an oxidation state of (n) ranging
from +2 to +6, selected from the Lanthanides or Group 3 to Group
16, of the Periodic Table; R.sup.1, R.sup.2, and R.sup.3 are
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; R.sup.4 is C.sub.1-C.sub.6
selected from the group methyl, ethyl, propyl, iso-propyl, butyl,
isobutyl, sec-butyl, pentyl, isopentyl, sec pentyl, hexyl,
sec-hexyl, tert-butyl tert-amyl, and valeraldyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1-4; (x)=1 to 6.
[0020] In yet another aspect, the present invention is a compound
from Formula 1, wherein (L) is an alkoxy anion, as represented by
Structure A2:
##STR00003##
[0021] wherein, M is a metal with an oxidation state of (n) ranging
from +2 to +6, selected from the Lanthanides or Group 3 to Group
16, of the Periodic Table; R.sup.1, R.sup.2 and R.sup.3 are
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; R.sup.4 is C.sub.1-C.sub.6
selected from the group consisting of methyl, ethyl, propyl,
iso-propyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec
pentyl, hexyl, sec-hexyl, tert-butyl tert-amyl, and valeraldyl; (Z)
is a neutral coordinating ligand selected from the group consisting
of an alkyl amine, polyalkylamine, ether, polyether, imidazole,
pyridine, alkyl substituted pyridine, pyrimidine, alkyl substituted
pyrimidine, and oxazole; (y)=1-4; (x)=1 to 6.
[0022] In yet another aspect, the present invention is a compound
from Formula 1, wherein (L) is a cyclopentadienyl anion, as
represented by Structure B
##STR00004##
[0023] wherein, M is a metal with an oxidation state of (n) ranging
from +2 to +6, selected from the Lanthanides or Group 3 to Group
16, of the Periodic Table; R.sup.1, R.sup.2, R.sup.3, and R.sup.5
are independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec-pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1-4; (x)=1 to 6; (m)=1 to 5.
[0024] In yet another aspect, the present invention is a compound
from Formula 1, wherein (L) is a pyrrolyl anion, as represented by
Structure C:
##STR00005##
[0025] wherein, M is a metal with an oxidation state of (n) ranging
from +2 to +6, selected from the Lanthanides or Group 3 to Group
16, of the Periodic Table; R.sup.1, R.sup.2, R.sup.3 and R.sup.6
are independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec-pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1 to 4; (x)=1 to 6; (p)=1 to 4.
[0026] In yet another aspect, the present invention is a compound
from Formula 1, wherein (L) is an imidazolate anion, as represented
by Structure D:
##STR00006##
[0027] wherein, M is a metal with an oxidation state of (n) ranging
from +2 to +6, selected from the Lanthanides or Group 3 to Group
16, of the Periodic Table; R.sup.1, R.sup.2, R.sup.3 and Ware
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec-pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (y)=1 to 4; (x)=1 to 6; (q)=1, 2 or 3.
[0028] In yet another aspect, the present invention is a compound
from formula 1, wherein (L) is a pyrazolate anion, as represented
by Structure E:
##STR00007##
[0029] wherein M is a metal with an oxidation state of (n) ranging
from +2 to +6 selected from the Lanthanides or Group 3 to Group 16
of the Periodic Table; (n) ranges from +2 to +6; R.sup.1, R.sup.2,
R.sup.3 and R.sup.8 are independently H or C.sub.1-C.sub.6 selected
from the group consisting of: methyl, ethyl, propyl, iso-propyl,
butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec-pentyl, hexyl,
sec-hexyl, tert-butyl, valeraldyl and tert-amyl; (Z) is a neutral
coordinating ligand selected from the group consisting of an alkyl
amine, polyalkylamine, ether, polyether, imidazole, pyridine, alkyl
substituted pyridine, pyrimidine, alkyl substituted pyrimidine, and
oxazole; (x)=1 to 4; r=1, 2 or 3; (y)=1 to 4.
[0030] In yet another aspect, the present invention provides a
compound represented by Formula 2:
##STR00008##
[0031] wherein M is a metal with an oxidation state of (n) ranging
from +2 to +6 selected from the Lanthanides or Group 3 to Group 16
of the Periodic Table; R.sup.9, R.sup.10, R.sup.11 and R.sup.12 are
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec-pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; (L) represents an anion or
anions selected from the group consisting of: alkyl substituted
enolate anion, alkoxy, guanidinate, amidinate, dialkylamide,
diketonate, ketoiminate, diiminate, cyclopentadienyl, alkyl
substituted cyclopentadienyl, alkoxysubstituted cyclopentadienyl,
aminosubsitituted cyclopentadienyl, pyrrolyl, alkyl substituted
pyrrolyl, alkoxysubstituted pyrrolyl, aminosubsitituted pyrrolyl,
alkyl substituted imidazolate, and alkoxysubstituted imidazolate;
(Z) is a neutral coordinating ligand selected from the group
consisting of an alkyl amine, polyalkylamine, ether, polyether,
imidazole, pyridine, alkyl substituted pyridine, pyrimidine, alkyl
substituted pyrimidine, and oxazole; (x)=1 to 3; (y)=1 to 4.
[0032] In yet another aspect, the present invention is a compound
represented by Formula 3:
##STR00009##
[0033] wherein M is a metal with an oxidation state of (n) ranging
from +2 to +6 selected from the Lanthanides or Group 3 to Group 16
of the Periodic Table; R.sup.13, R.sup.14 and R.sup.15 are
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec-pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; (L) represents an anion or
anions selected from the group consisting of: alkyl substituted
enolate anion, alkoxy, guanidinate, amidinate, dialkylamide,
diketonate, ketoiminate, diiminate, cyclopentadienyl, alkyl
substituted cyclopentadienyl, alkoxysubstituted cyclopentadienyl,
aminosubsitituted cyclopentadienyl, pyrrolyl, alkyl substituted
pyrrolyl, alkoxysubstituted pyrrolyl, aminosubsitituted pyrrolyl;
alkyl substituted imidazolate, and alkoxysubstituted imidazolate;
(Z) is a neutral coordinating ligand selected from the group
consisting of an alkyl amine, polyalkylamine, ether, polyether,
imidazole, pyridine, alkyl substituted pyridine, pyrimidine, alkyl
substituted pyrimidine, and oxazole; (x)=1 to 3; (y)=1 to 4.
[0034] In yet another aspect, the present invention is a compound
represented by Structure 4:
##STR00010##
[0035] wherein M is a metal with an oxidation state of (n) ranging
from +2 to +6 selected from the Lanthanides or Group 3 to Group 16
of the Periodic Table; R.sup.16, R.sup.17 are independently H or
C.sub.1-C.sub.6 selected from the group consisting of: methyl,
ethyl, propyl, iso-propyl, butyl, isobutyl, sec-butyl, pentyl,
isopentyl, sec-pentyl, hexyl, sec-hexyl, tert-butyl, tert-amyl, and
valeraldyl; (L) represents an anion or anions selected from the
group consisting of: alkyl substituted enolate anion, alkoxy,
guanidinate, amidinate, dialkylamide, diketonate, ketoiminate,
diiminate, cyclopentadienyl, alkyl substituted cyclopentadienyl,
alkoxysubstituted cyclopentadienyl, aminosubsitituted
cyclopentadienyl, pyrrolyl, alkyl substituted pyrrolyl,
alkoxysubstituted pyrrolyl, aminosubsitituted pyrrolyl; alkyl
substituted imidazolate, and alkoxysubstituted imidazolate; (Z) is
a neutral coordinating ligand selected from the group consisting of
an alkyl amine, polyalkylamine, ether, polyether, imidazole,
pyridine, alkyl substituted pyridine, pyrimidine, alkyl substituted
pyrimidine, and oxazole; (x)=1 to 3; (y)=1 to 4.
[0036] In yet another aspect, the present invention is a compound
represented by Formula 5:
##STR00011##
[0037] wherein M is a metal with an oxidation state of (n) ranging
from +2 to +6 selected from the Lanthanides or Group 3 to Group 16
of the Periodic Table; R.sup.18, R.sup.19 R.sup.20 and R.sup.21 are
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, isobutyl,
sec-butyl, pentyl, isopentyl, sec-pentyl, hexyl, sec-hexyl,
tert-butyl, tert-amyl, and valeraldyl; (L) represents an anion or
anions selected from the group consisting of: alkyl substituted
enolate anion, alkoxy, guanidinate, amidinate, dialkylamide,
diketonate, ketoiminate, diiminate, cyclopentadienyl, alkyl
substituted cyclopentadienyl, alkoxysubstituted cyclopentadienyl,
aminosubsitituted cyclopentadienyl, pyrrolyl, alkyl substituted
pyrrolyl, alkoxysubstituted pyrrolyl, aminosubsitituted pyrrolyl;
alkyl substituted imidazolate, and alkoxysubstituted imidazolate;
(Z) is a neutral coordinating ligand selected from the group
consisting of an alkyl amine, polyalkylamine, ether, polyether,
imidazole, pyridine, alkyl substituted pyridine, pyrimidine, alkyl
substituted pyrimidine, and oxazole; (x)=1 to 3; (y)=1 to 4.
[0038] In yet another aspect, the present invention provides a
method for forming a metal-containing film by utilizing these
enolate and dienolate precursors of this disclosure in solutions
for spin-on thin film growth.
[0039] In yet another aspect, the present invention provides a
method for forming a metal-containing film by utilizing these
volatile enolate and dienolate precursors as CVD or cyclic CVD
precursors whereby the precursor and a reagent are flowed
simultaneously into the reaction chamber to deposit a film onto a
heated substrate. This can be run continuously or in a pulsed
mode.
[0040] In yet another aspect, the present invention provides a
method for forming a metal-containing film by ALD, the method
comprises the steps of: a. introducing a metal-containing precursor
of this disclosure in a vapor state into a reaction chamber and
chemisorbing the metal-containing precursor onto a substrate which
is heated; b. purging away the unreacted metal-containing
precursor; c. introducing an oxidizing source such as, but limited
to, oxygen, ozone, nitrous oxide or water onto the heated substrate
to react with the adsorbed metal-containing precursor; and d.
purging away the unreacted oxidizing source. This sequence of
cycles is then repeated to build up the metal oxide film
thickness.
[0041] In a preferred embodiment of this invention, the precursor
is a liquid or a solid with melting point below 100.degree. C.
[0042] While not wishing to be bound by theory, advantages of these
precursors is that they are low melting point solids or liquid and
thermally stable, as demonstrated by their TGA performance, and are
reactive under ALD or CVD conditions to allow the deposition of
highly conformal metal oxide films by atomic layer deposition or
cyclic chemical vapor deposition at temperatures ranging from
100.degree. C. to 600.degree. C. The novel enolate and dienolate
precursors of this disclosure can also be utilized to deposit one
or more metal elements contained in mixed metal oxide films such
as, but not limited to strontium titanate (STO) or barium strontium
titanate (BST).
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0043] So that the manner in which the above recited features of
the invention can be understood in detail, a more particular
description of the invention, briefly summarized above, may be had
by reference to embodiments, some of which are illustrated in the
appended drawings. It is to be noted, however, that the appended
drawings illustrate only typical embodiments of this invention and
are therefore not to be considered limiting of its scope, for the
invention may admit to other equally effective embodiments.
[0044] FIG. 1 is a schematic representation of a crystal structure
of di-titanium bis
(2,2,5,5-tetramethylhex-3-en-3-olato)hexa(ethoxy), characterized by
X-ray single crystal diffraction;
[0045] FIG. 2 is a schematic representation of a crystal structure
of
bis(2,2,5,5-tetramethylhex-3-en-3-olato)(bis(iso-propoxy)titanium,
characterized by X-ray single crystal diffraction; and
[0046] FIG. 3 is a graph of a thermogravimetric analysis (TGA) of
bis(2,2,5,5-tetramethylhex-3-en-3-olato)(bis(iso-propoxy)titanium.
[0047] FIG. 4 is a schematic representation of a crystal structure
of
tris(2,2,5,5-tetramethylhex-3-en-3-olato)(dimethylamido)titanium.
[0048] FIG. 5 is a graph of a thermogravimetric analysis (TGA) of
tris(2,2,5,5-tetramethylhex-3-en-3-olato)(dimethylamido)titanium.
[0049] FIG. 6 is a schematic representation of a crystal structure
of
bis(2,2,7,7-tetramethylocta-3,5-diene-3,6-diolato)bis(dimethylamino)titan-
ium.
DETAILED DESCRIPTION OF THE INVENTION
[0050] Disclosed herein are liquid or low-melting point solid
metal-enolate complexes comprising an enolate moiety that are
suitable, for example, as precursors in chemical vapor deposition
processes. Novel dienolate metal complexes are also described. The
complexes and compositions are useful for fabricating metal
containing films on substrates such as silicon, metal nitride,
metal oxide, metal oxynitride, metal silicate, and other metal
containing layers via chemical vapor deposition (CVD), cyclical
chemical vapor deposition (CCVD), or atomic layer deposition (ALD)
or Atomic Vapor Deposition (AVD) processes. The deposited metal
films have applications ranging from computer chips, optical
device, magnetic information storage, to metallic catalyst coated
on a supporting material.
[0051] Also disclosed herein are methods for preparing these
precursors, as well as their use in vapor deposition processes,
particularly CVD or ALD deposition processes.
[0052] The metal-containing precursors of the present invention
comprise an enolate complex and are represented by Formula 1 and
dienolate complexes represented by Formulae 2, 3, 4 and 5. In one
embodiment of the present invention, M is selected from the group
consisting of a lanthanide metal and groups 3 to 16 of the periodic
table. In another embodiment M is selected from lanthanide, Ti, Zr,
Hf, V, Nb, Ta, Cr, Mo, W, and Mn. In a preferred embodiment of the
present invention, M is a Group 4 metal. In a most preferred
embodiment of the present invention, M is Ti. Exemplary examples
are
bis(2,2,5,5-tetramethylhex-3-en-3-olato)hexa(ethoxy)di-titanium,
bis(2,2,5,5-tetramethylhex-3-en-3-olato)(bis(iso-propoxy)titanium,
tris(2,2,5,5-tetramethylhex-3-en-3-olato)(dimethylamido)titanium.
and
bis(2,2,7,7-tetramethylocta-3,5-diene-3,6-diolato)bis(dimethylamino)titan-
ium.
The metal-containing precursors of the present invention comprising
a dienolate ligand and are represented by Formulae 2, 3, 4 and 5.
In one embodiment of the present invention, M is selected from the
group consisting of a lanthanide metal and groups 3 to 16 of the
periodic table. In another embodiment M is selected from
lanthanide, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Mn. In a
preferred embodiment of the present invention, M is a Group 4
metal. In a most preferred embodiment of the present invention, M
is Ti. An exemplary complex is
bis(2,2,7,7-tetramethylocta-3,5-diene-3,6-diolato)bis(dimethylamino)titan-
ium.
[0053] In a preferred embodiment of the present invention, the
groups R.sup.1, R.sup.2 and R.sup.3 of the enolate anion of formula
1 are C.sub.1-C.sub.6 alkyl. In another embodiment of the present
invention, R.sup.1, R.sup.2 or R.sup.3 are independently selected
from the group consisting of: hydrogen, methyl, ethyl, iso-propyl,
n-propyl, sec-butyl, iso-butyl, t-butyl, and t-amyl. In preferred
embodiments, the groups R.sup.1, R.sup.2 and R.sup.3 are carefully
selected so as to provide a coordination environment around the
metal center such as to shield it to allow the complex to form as a
volatile precursor. Additionally, R.sup.1, R.sup.2 and R.sup.3 are
also selected to permit a low melting point of the enolate
complex.
[0054] In a preferred embodiment of the present invention, the
groups R.sup.9, R.sup.10 R.sup.11 and R.sup.12 of the dienolate
anion of formula 2 are C.sub.4-C.sub.6 alkyl. In another embodiment
of the present invention, R.sup.9, R.sup.10 R.sup.11 and R.sup.12
are H or C.sub.1-C.sub.6 alkyl selected from the group consisting
of: methyl, ethyl, iso-propyl, n-propyl, sec-butyl, iso-butyl,
t-butyl, and t-amyl. In preferred embodiments, the groups R.sup.9,
R.sup.10 R.sup.11 and R.sup.12 are carefully selected so as to
provide a coordination environment around the metal center such as
to shield it to allow the complex to form as a volatile precursor.
Additionally, R.sup.9, R.sup.10 R.sup.11 and R.sup.12 are also
selected to permit a low melting point of the dienolate
complex.
[0055] In a preferred embodiment of the present invention, the
groups and R.sup.13, R.sup.14 and R.sup.15 of the dienolate anion
of formula 3 are C.sub.1-C.sub.6 alkyl. In another embodiment of
the present invention, R.sup.13, R.sup.14 and R.sup.15 are H or
C.sub.1-C.sub.6 selected from the group consisting of: methyl,
ethyl, iso-propyl, n-propyl, sec-butyl, iso-butyl, t-butyl, and
t-amyl. In preferred embodiments the groups R.sup.13, R.sup.14 and
R.sup.15 are carefully selected so as to provide a coordination
environment around the metal center, such as to shield it to allow
the complex to form as a volatile precursor. Additionally,
R.sup.13, R.sup.14 and R.sup.15 are also selected to permit a low
melting point of the dienolate complex.
[0056] In a preferred embodiment of the present invention, the
groups R.sup.16 and R.sup.17 of the dienolate anion of Formula 4
are independently H or C.sub.1-C.sub.6 alkyl. In another embodiment
of the present invention, R.sup.16 and R.sup.17 are independently H
or C.sub.1-C.sub.6 alkyl selected from the group consisting of:
methyl, ethyl, iso-propyl, n-propyl, sec-butyl, iso-butyl, t-butyl,
and t-amyl. In preferred embodiments, the groups R.sup.16 and
R.sup.17 are carefully selected so as to provide a coordination
environment around the metal center, such as to shield it to allow
the complex to form as a volatile precursor. Additionally, R.sup.16
and R.sup.17 are also selected to permit a low melting point of the
dienolate complex.
[0057] In a preferred embodiment of the present invention, the
groups R.sup.18, R.sup.19, R.sup.20 and R.sup.21 of the dienolate
anion of Formula 5 are H or C.sub.1-C.sub.6 alkyl. In another
embodiment of the present invention, R.sup.18, R.sup.19, R.sup.20
and R.sup.21 are independently H or C.sub.1-C.sub.6 alkyl selected
from the group consisting of: methyl, ethyl, iso-propyl, n-propyl,
sec-butyl, iso-butyl, t-butyl, and t-amyl. In preferred
embodiments, the groups R.sup.18, R.sup.19, R.sup.20 and R.sup.21
are carefully selected so as to provide a coordination environment
around the metal center, such as to shield it to allow the complex
to form as a volatile precursor. Additionally, R.sup.18, R.sup.19,
R.sup.20 and R.sup.21 are also selected to permit a low melting
point of the dienolate complex.
[0058] The term "alkyl" as used herein includes linear, branched,
or cyclic alkyl groups, comprising from 1 to 10 carbon atoms, from
1 to 6 carbon atoms, from 1 to 3 carbon atoms, from 3 to 5 carbon
atoms, from 4 to 6 carbons atoms, or variations of the foregoing
ranges. Exemplary alkyl groups include, but are not limited to,
methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,
tert-butyl, tert-amyl, n-pentyl, n-hexyl, pentyl, isopentyl,
tert-butyl and tert-amyl, valeraldyl, cyclopentyl, and cyclohexyl.
The term "alkyl" applies also to alkyl moieties contained in other
groups, such as alkycyclopentadienyl, alkylpyrrolyl,
alkylimidazolate, and alkylpyrazolate. The term "bulky" as used
herein describes alkyl groups that are more sterically hindered
compared to linear alkyl groups having the same number of carbon
atoms and may include, for example, branched alkyl groups, cyclic
alkyl groups, or alkyl groups having one or more side changes
and/or substituents.
[0059] In preferred embodiments of the present invention, (L) shown
in Formulae 1, 2, 3 and 4 are selected from the group consisting
of: amidinate, guanidinate, alkoxy, dialkylamide, diketonate,
ketoiminate, diiminate, cyclopentadienyl, alkyl substituted
cyclopentadienyl, alkoxy substituted cyclopentadienyl, amino
substituted cyclopentadienyl, pyrrolyl, alkyl substituted pyrrolyl,
alkoxy substituted pyrrolyl, and amino substituted pyrrolyl; alkyl
substituted imidazoyl, alkoxy substituted imidazolate,
aminosubsitituted imidazolate, pyrazolate or alkyl substituted
pyrazolate.
[0060] In preferred embodiments of the present invention, the
metal-containing precursor is a low melting solid or liquid.
Exemplary melting point temperatures for the precursors disclosed
herein include ranges having any one or more of the following
endpoints: 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35,
and/or 30.degree. C. Examples of particular melting point ranges
include, but are not limited to, 100.degree. C. or less, 75.degree.
C. or less, or 60.degree. C. or less.
[0061] In another embodiment of the present invention, the
metal-containing precursors are represented by Structure A1:
##STR00012##
[0062] wherein M is the Lanthanides or from Group 3 to 16 of the
Periodic Table. Preferably the metal M is selected from Group 4. In
a preferred embodiment, M is selected from the group consisting of:
Ti, Zr, and Hf. In a further preferred embodiment M is Ti. R.sup.1,
R.sup.2 and R.sup.3 are independently H or C.sub.1-C.sub.6 selected
from the group consisting of: methyl, ethyl, propyl, iso-propyl,
butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec-pentyl, hexyl,
sec-hexyl, and tert-butyl. In a further preferred embodiment
R.sup.1 and R.sup.2 are tert-butyl and (L) is alkoxide anion. An
exemplary precursor of Structure A1 includes, but is not limited
to:
Bis(2,2,5,5-tetramethylhex-3-en-3-olato)(bis(iso-propoxy)titanium.
[0063] In another embodiment of the present invention, the
metal-containing precursors are represented by Structure A2:
##STR00013##
[0064] wherein M is the Lanthanides or from Group 3 to 16 of the
Periodic Table. Preferably, the metal M is selected from Group 4.
In a preferred embodiment, M is selected from the group consisting
of: Ti, Zr, and Hf. In a further preferred embodiment M is Ti.
R.sup.1, R.sup.2 and R.sup.3 are selected independently from the
group consisting of: hydrogen, methyl, ethyl, propyl, iso-propyl,
butyl, isobutyl, sec-butyl, pentyl, isopentyl, sec-pentyl, hexyl,
sec-hexyl, and tert-butyl. In a further preferred embodiment,
R.sup.1 and R.sup.2 are tert-butyl and (L) is alkoxide. An
exemplary precursor of Structure A2 includes, but is not limited
to:
bis(2,2,5,5-tetramethylhex-3-en-3-olato)hexa(ethoxy)di-titanium.
[0065] In another embodiment of the present invention, the
metal-containing precursors are represented by Formula 1
##STR00014##
[0066] wherein M is the Lanthanides or from Group 3 to 16 of the
Periodic Table. Preferably, the metal M is selected from Group 4.
In a preferred embodiment, M is selected from the group consisting
of: Ti, Zr, and Hf. In a further preferred embodiment, M is Ti.
R.sup.1, R.sup.2 and R.sup.3 are independently H or C.sub.1-C.sub.6
selected from the group consisting of: methyl, ethyl, propyl,
iso-propyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl,
sec-pentyl, hexyl, sec-hexyl, tert-butyl, valeraldyl, tert-butyl,
and tert-amyl. In a further preferred embodiment, R.sup.1 and
R.sup.2 are tert-butyl and (L) represents an amide anion. An
exemplary precursor of Formula 1 includes, but is not limited to:
tris(2,2,5,5-tetramethylhex-3-en-3-olato)(dimethylamido)titanium.
[0067] In another embodiment of the present invention, the
metal-containing precursors are represented by Formula 2:
##STR00015##
[0068] wherein M is the Lanthanides or from Group 3 to 16 of the
Periodic Table. Preferably, the metal M is selected from Group 4.
In a preferred embodiment, M is selected from the group consisting
of: Ti, Zr, and Hf. In a further preferred embodiment, M is Ti.
R.sup.1, R.sup.2 and R.sup.3 are independently H or C.sub.1-C.sub.6
selected from the group consisting of: methyl, ethyl, propyl,
iso-propyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl,
sec-pentyl, hexyl, sec-hexyl, tert-butyl, valeraldyl, tert-butyl,
and tert-amyl. In a further preferred embodiment, R.sup.9 and
R.sup.12 are tert-butyl, R.sup.10 and R.sup.11 are hydrogen, and
(Z) is an alkylamine. An exemplary precursor of Formula 2 includes,
but is not limited to:
bis(2,2,7,7-tetramethylocta-3,5-dien-3,6-diolato)bis(dimethylamino)titani-
um.
[0069] In another embodiment of the present invention, the
metal-containing precursors are represented by Structure B, wherein
M is a metal from Group 3 to Group 7 of the Periodic Table;
R.sup.1, R.sup.2, R.sup.3, and R.sup.5 are independently H or
C.sub.1-C.sub.6 selected from the group consisting methyl, ethyl,
propyl, iso-propyl, and tert-butyl; n=3, to 6; and m=1 to 5.
##STR00016##
[0070] In preferred embodiments, M is selected from the group
consisting of: Sc, La, V, Nb, Ta, Cr, Mo, W, Mn, Re, Ce, Pr, Sm,
Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Ti, Zr, and Hf. In other preferred
embodiments, M is selected from the group consisting of: Sc, La,
Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, and Re.
[0071] Exemplary precursors of Structure B include, but not limited
to, [0072]
methylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)titanium,
[0073]
methylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)zirconium,
[0074]
methylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)hafnium,
[0075]
ethylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)titanium,
[0076]
ethylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)zirconium,
[0077]
ethylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)hafnium,
[0078]
methylcyclopentadienyltri(4,4-dimethylpent-2-en-3-olato)titanium,
[0079]
methylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)zirconiu-
m, [0080]
methylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)hafniu-
m, [0081]
ethylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)titaniu-
m, [0082]
ethylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)zirconi-
um, [0083]
ethylcyclopentadienyltri(2,2,5-trimethylhex-3-en-3-olato)hafniu- m,
[0084]
methylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)ti-
tanium, [0085]
methylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)zirconium,
[0086]
methylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)hafn-
ium, [0087]
ethylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)titanium,
[0088]
ethylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)zirco-
nium, and [0089]
ethylcyclopentadienyltri(2,2,5,5-tetramethylhex-3-en-3-olato)hafnium.
[0090] In another embodiment of the present invention, the
metal-containing precursors are represented by Structure C, wherein
M is a metal selected from the lanthanides and Group 3 to Group 16
of the Periodic Table; R.sup.1, R.sup.2 and R.sup.3 are
independently H or C.sub.1-C.sub.6 selected from the group
consisting of: methyl, ethyl, propyl, iso-propyl, butyl, sec-butyl,
tert-butyl and tert-amyl; p=1, 2, 3, or 4; (n)=3, 4, 5, 6; and x=1,
to 5.
##STR00017##
[0091] In preferred embodiments, M is selected from the group
consisting of: Sc, La, V, Nb, Ta, Cr, Mo, W, Mn, Re, Ce, Pr, Sm,
Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Ti, Zr, and Hf. In one preferred
embodiments, M is selected from the group consisting of: Sc, La,
Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, and Re. In more preferred
embodiments of the present invention, M is selected from the group
consisting of: La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Ti,
Zr, and Hf.
[0092] The method disclosed herein deposits metal-containing films
using atomic layer deposition (ALD) or chemical vapor deposition
(CVD) processes. Examples of suitable deposition processes for the
method disclosed herein include, but are not limited to, cyclic CVD
(CCVD), MOCVD (Metal Organic CVD), thermal chemical vapor
deposition, plasma enhanced chemical vapor deposition ("PECVD"),
high density PECVD, photon assisted CVD, plasma-photon assisted
("PPECVD"), cryogenic chemical vapor deposition, chemical assisted
vapor deposition, hot-filament chemical vapor deposition, CVD of a
liquid polymer precursor, deposition from supercritical fluids, and
low energy CVD (LECVD). In certain embodiments, the metal
containing films are deposited via plasma enhanced ALD (PEALD) or
plasma enhanced cyclic CVD (PECCVD) process. In these embodiments,
the deposition temperature may be relatively lower, or may range
from 200.degree. C. to 400.degree. C., and may allow for a wider
process window to control the specifications of film properties
required in end-use applications. Exemplary deposition temperatures
for the PEALD or PECCVD deposition include ranges having any one or
more of the following endpoints: 200, 225, 250, 275, 300, 325, 350,
375, 400, 425, 450, 475, 500, 525, 550, 575, 600, 625, 650, 675
and/or 700.degree. C.
[0093] In one embodiment of the method disclosed herein, a metal
silicate or metal silicon oxynitride film is formed onto at least
one surface of a substrate using a metal-containing precursor of
Formulae I, 2, 3, 4 or 5 of the present invention, a
silicon-containing precursor, an oxygen source, and optionally a
nitrogen source. Although metal-containing and silicon-containing
precursors typically react in either liquid form or gas phase,
thereby preventing film formation, the method disclosed herein
avoids pre-reaction of the metal containing and silicon-containing
precursors by using ALD or CCVD methods that separate the
precursors prior to and/or during the introduction to the reactor.
In this connection, deposition techniques, such as an ALD or CCVD
processes, are used to deposit the metal-containing film.
[0094] For example, in certain embodiments, an ALD process is used
to deposit the metal-containing film. In a typical ALD process, the
film is deposited by exposing the substrate surface alternatively
to the metal enolate, then the silicon-containing precursor or to
the metal dienolate then the silicon-containing precursor. Film
growth proceeds by self-limiting control of surface reaction, the
pulse length of each precursor, and the deposition temperature.
However, once the surface of the substrate is saturated, the film
growth ceases. In yet another embodiment, the metal-containing film
may be deposited using a CCVD process. In this embodiment, the CCVD
process may be performed using a higher temperature range than the
ALD window, or from 350.degree. C. to 800.degree. C. thereby
preventing, for example, precursor decomposition. Exemplary
deposition temperatures for the CCVD deposition include ranges
having any one or more of the following endpoints (provided in
degrees Celsius): 200, 225, 250, 275, 300, 325, 350, 375, 400, 425,
450, 475, 500, 525, 550, 575, 600, 625, 650, 675, 700, 725, 750,
775 and 800.degree. C.
[0095] In certain embodiments, the method disclosed herein forms
the metal oxide films using metal enolate or dienolate precursors
and an oxygen source.
[0096] As mentioned previously, the method disclosed herein forms
the metal-containing films using at least one metal precursor such
as, for example, the metal-containing precursors having formula I
described herein, optionally at least one silicon-containing
precursor, optionally an oxygen source, optionally an additional
metal-containing or other metal-containing precursor, optionally a
reducing agent, and optionally a nitrogen source. Although the
precursors and sources used herein may be sometimes described as
"gaseous," it is understood that the precursors can be either
liquid or solid which are transported with or without an inert gas
into the reactor via direct vaporization, bubbling or sublimation.
In some case, the vaporized precursors can pass through a plasma
generator. Alternatively, the enolate and dienolate precursors
described herein can also be dissolved in a solvent and the
resulting solution flash evaporated by a Direct Liquid Injection
(DLI) system to deliver precursor vapor to the CVD or ALD
chamber.
[0097] In certain embodiments, other metal-containing precursors
can be used in conjunction with the metal-containing precursors of
the present invention. Metal commonly used in semiconductor
fabrication include: titanium, tantalum, tungsten, hafnium,
zirconium, cerium, zinc, thorium, bismuth, lanthanum, strontium,
barium, lead, and combinations thereof. Examples of other
precursors, containing these metals include, but are not limited
to: tetrakis(dimethylamino)zirconium (TDMAZ),
tetrakis(diethylamino)zirconium (TDEAZ),
tetrakis(ethylmethylamino)zirconium (TEMAZ),
tetrakis(dimethylamino)hafnium (TDMAH),
tetrakis(diethylamino)hafnium (TDEAH), and
tetrakis(ethylmethylamino)hafnium (TEMAH),
tetrakis(dimethylamino)titanium (TDMAT),
tetrakis(diethylamino)titanium (TDEAT),
tetrakis(ethylmethylamino)titanium (TEMAT), tert-butylimino
tri(diethylamino)tantalum (TBTDET), tert-butylimino
tri(dimethylamino)tantalum (TBTDMT), tert-butylimino
tri(ethylmethylamino)tantalum (TBTEMT), ethylimino
tri(diethylamino)tantalum (EITDET), ethylimino
tri(dimethylamino)tantalum (EITDMT), ethylimino
tri(ethylmethylamino)tantalum (EITEMT), tert-amylimino
tri(dimethylamino)tantalum (TAIMAT), tert-amylimino
tri(diethylamino)tantalum, pentakis(dimethylamino)tantalum,
tert-amylimino tri(ethylmethylamino)tantalum,
bis(tert-butylimino)bis(dimethylamino)tungsten (BTBMW),
bis(tert-butylimino)bis(diethylamino)tungsten,
bis(tert-butylimino)bis(ethylmethylamino)tungsten,
bis(2,2,6,6-tetramethyl-3,5-heptanedionato)strontium,
bis(2,2,6,6-tetramethyl-3,5-heptanedionato)barium, dibariun
tetra(2,4,5-tri-tert-butylimidazolate), dibarium
tetra(2-tert-butyl-4,5-di-tert-amylimidazolate), distrontiun
tetra(2,4,5-tri-tert-butylimidazolate), distrontium
tetra(2-tert-butyl-4,5-di-tert-amylimidazolate),
M(R.sub.nC.sub.5H.sub.5-n).sub.2, wherein (n)=1 to 5 and R is
selected from linear or branched C.sub.1-6 alkyls;
M(R.sub.nC.sub.4NH.sub.4-n).sub.2, wherein (n)=2 to 4, R is
selected from linear or branched C.sub.1-6 alkyls, and
M(R.sub.nN.sub.2H.sub.3-n).sub.2, where (n)=2 to 3, R is selected
from linear or branched C.sub.1-6 alkyls, and combinations
thereof.
[0098] In one embodiment, the metal-containing precursors, that can
be used in addition to the Group 4 metal precursors described
herein to provide a metal-containing film, are polydentate
.beta.-ketoiminates which are described, for example, in
Applicants' co-pending application US2007/0248754A1, U.S. Ser. No.
11/945,678 filed on Nov. 27, 2007, Applicants' co-pending
application U.S. Ser. No. 12/266,806 which was filed on Nov. 11,
2008 Applicants' patents U.S. Pat. No. 7,691,984, U.S. Pat. No.
7,723,493, all of which are incorporated herein by reference in
their entirety.
[0099] In embodiments wherein the metal film deposited is a metal
silicate, the deposition process further involves the introduction
of at least one silicon-containing precursor. Examples of suitable
silicon-containing precursors include a monoalkylaminosilane
precursor, a hydrazinosilane precursor, or combinations
thereof.
[0100] In certain embodiments, the silicon-containing precursor
comprises a monoalkylaminosilane precursor having at least one N--H
fragment and at least one Si--H fragment. Suitable
monoalkylaminosilane precursors containing both the N--H fragment
and the Si--H fragment include, for example,
bis(tert-butylamino)silane (BTBAS), tris(tert-butylamino)silane,
bis(iso-propylamino)silane, tris(iso-propylamino)silane, and
mixtures thereof.
[0101] In one embodiment, the monoalkylaminosilane precursor has
the formula (R.sup.5NH).sub.nSiR.sup.6.sub.mH.sub.4-(n+m) wherein
R.sup.5 and R.sup.6 are the same or different and independently
selected from the group consisting of alkyl, vinyl allyl, phenyl,
cyclic alkyl, fluoroalkyl, and silylalkyl and wherein n is a number
ranging from 1 to 3, m is a number ranging from 0 to 2, and the sum
of "n+m" is a number that is less than or equal to 3.
[0102] In another embodiment, the silicon-containing precursor
comprises a hydrazinosilane having the formula
(R.sup.7.sub.2N--NH).sub.xSiR.sup.8.sub.yH.sub.4-(x+y) wherein
R.sup.7 and R.sup.8 are same or different and independently
selected from the group consisting of alkyl, vinyl, allyl, phenyl,
cyclic alkyl, fluoroalkyl, silylalkyls and wherein x is a number
ranging from 1 to 2, y is a number ranging from 0 to 2, and the sum
of "x+y" is a number that is less than or equal to 3. Examples of
suitable hydrazinosilane precursors include, but are not limited
to, bis(1,1-dimethylhydrazino)-silane,
tris(1,1-dimethylhydrazino)silane,
bis(1,1-dimethylhydrazino)ethylsilane,
bis(1,1-dimethylhydrazino)isopropylsilane,
bis(1,1-dimethylhydrazino)vinylsilane, and mixtures thereof.
[0103] Depending upon the deposition method, in certain
embodiments, the silicon-containing precursor may be introduced
into the reactor at a predetermined molar volume, or from about 0.1
to about 1000 micromoles. In this or other embodiments, the
silicon-containing precursor may be introduced into the reactor for
a predetermined time period, or from about 0.001 to about 500
seconds.
[0104] The silicon-containing precursors react with the metal
hydroxyl groups formed by the reaction of the metal amide with the
oxygen source and become chemically adsorbed onto the surface of
the substrate which results in the formation of a silicon oxide or
a silicon oxynitride via metal-oxygen-silicon and
metal-oxygen-nitrogen-silicon linkages, thus providing the metal
silicate or the metal silicon oxynitride film.
[0105] As previously mentioned, some of the films deposited using
the methods described herein (e.g., metal silicate or the metal
silicon oxynitride films) may be formed in the presence of oxygen.
An oxygen source may be introduced into the reactor in the form of
at least one oxygen source and/or may be present incidentally in
the other precursors used in the deposition process. Suitable
oxygen source gases may include, for example, water (H.sub.2O)
(e.g., deionized water, purifier water, and/or distilled water),
oxygen (O.sub.2), oxygen plasma, ozone (O.sub.3), NO, N.sub.2O,
NO.sub.2, carbon monoxide (CO), carbon dioxide (CO.sub.2) and
combinations thereof. In certain embodiments, the oxygen source
comprises an oxygen source gas that is introduced into the reactor
at a flow rate ranging from about 1 to about 2000 square cubic
centimeters (sccm) or from about 1 to about 1000 sccm. The oxygen
source can be introduced for a time that ranges from about 0.1 to
about 100 seconds. In one particular embodiment, the oxygen source
comprises water having a temperature of 10.degree. C. or
greater.
[0106] In this or other embodiments wherein the film is deposited
by an ALD process, the precursor pulse can have a pulse duration
that is greater than 0.01 seconds, and the oxidant pulse duration
can have a pulse duration that is greater than 0.01 seconds, while
the water pulse duration can have a pulse duration that is greater
than 0.01 seconds. In yet another embodiment, the purge duration
between the pulses that can be as low as 0 seconds.
[0107] The deposition methods disclosed herein may involve one or
more purge gases. The purge gas, which is used to purge away
unconsumed reactants and/or reaction byproducts, is an inert gas
that does not react with the precursors and may preferably be
selected from the group consisting of Ar, N.sub.2, He, H.sub.2 and
mixture thereof. In certain embodiments, a purge gas such as Ar is
supplied into the reactor at a flow rate ranging from about 10 to
about 2000 sccm for about 0.1 to 1000 seconds, thereby purging the
unreacted material and any byproduct that remain in the
reactor.
[0108] In certain embodiments, such as, for example, for those
embodiments where a metal silicon oxynitride film is deposited, an
additional gas such as a nitrogen source gas may be introduced into
the reactor. Examples of nitrogen source gases may include, for
example, NO, NO.sub.2, ammonia, hydrazine, monoalkylhydrazine,
dialkylhydrazine, and combinations thereof.
[0109] In one embodiment of the method described herein, the
temperature of the substrate in the reactor, i.e., a deposition
chamber, is about 600.degree. C. or below or about 500.degree. C.
or below or from 250 to 400.degree. C. In this or other
embodiments, the pressure may range from about 0.1 Torr to about
100 Torr or from about 0.1 Torr to about 5 Torr.
[0110] The respective step of supplying the precursors, the oxygen
source, and/or other precursors or source gases may be performed by
changing the time for supplying them to modify the stoichiometric
composition of the resulting metal silicate, metal silicon
oxynitride film, or other metal-containing film.
[0111] Energy is applied to the at least one of the precursor,
oxygen source gas, reducing agent, or combination thereof to induce
reaction and to form the metal-containing film on the substrate.
Such energy can be provided by, but not limited to, thermal,
plasma, pulsed plasma, helicon plasma, high density plasma,
inductively coupled plasma, X-ray, e-beam, photon, and remote
plasma methods. In certain embodiments, a secondary RF frequency
source can be used to modify the plasma characteristics at the
substrate surface. In embodiments wherein the deposition involves
plasma, the plasma-generated process may comprise a direct
plasma-generated process in which plasma is directly generated in
the reactor, or alternatively a remote plasma-generated process in
which plasma is generated outside of the reactor and supplied into
the reactor.
[0112] In yet another embodiment of the method disclosed herein,
the metal-containing film is formed using a vapor deposition method
that comprises the steps of: a. introducing a metal-containing
precursor of Formulae I, 2, 3, 4 or 5 in a vapor state into a
reaction chamber and chemisorbing the metal-containing precursor
onto a substrate which is heated; b. purging away the unreacted
metal-containing precursor; c. introducing an oxygen source onto
the heated substrate to react with the adsorbed metal-containing
precursor; and d. purging away the unreacted oxygen source. The
above steps define one cycle for the method described herein; and
the cycle can be repeated until the desired thickness of a
metal-containing film is obtained. In this or other embodiments, it
is understood that the steps of the methods described herein may be
performed in a variety of orders, may be performed sequentially or
concurrently (e.g., during at least a portion of another step), and
any combination thereof. The respective step of supplying the
precursors and the oxygen source gases may be performed by varying
the duration of the time for supplying them to modify the
stoichiometric composition of the resulting metal oxide film. For
multicomponent metal oxide films, a strontium-containing precursor,
a barium-containing precursor or both precursors can be alternately
introduced in step a into the reactor chamber to deliver the
elements of barium and strontium for film, such as barium strontium
titanate (BST)
[0113] The metal-containing precursor of the present invention or
the metal-containing precursor of the present invention in
conjunction with other metal containing precursors may be delivered
to the reaction chamber, such as a CVD or ALD reactor, in a variety
of ways. In one embodiment, a liquid delivery system may be
utilized. In an alternative embodiment, a combined liquid delivery
and flash vaporization process unit may be employed, such as, for
example, the turbo vaporizer manufactured by MSP Corporation of
Shoreview, Mn, to enable low volatility materials to be
volumetrically delivered, leading to reproducible transport and
deposition without thermal decomposition of the precursor. Both of
these considerations of reproducible transport and deposition
without thermal decomposition are essential for providing a
commercially acceptable copper CVD or ALD process.
[0114] In one embodiment of the method described herein, a cyclic
deposition process, such as CCVD, ALD, or PEALD, may be employed,
wherein a metal-containing precursor of the present invention or
its solution and an oxygen source such as, for example, ozone,
oxygen plasma or water plasma are employed. The gas lines
connecting from the precursor canisters to the reaction chamber are
heated to one or more temperatures ranging from about 150.degree.
C. to about 200.degree. C. depending upon the process requirements,
and the container of the metal-containing precursor is kept at one
or more temperatures ranging from about 100.degree. C. to about
190.degree. C. for bubbling whereas the solution comprising the
metal-containing precursor is injected into a vaporizer kept at one
or more temperatures ranging from about 150.degree. C. to about
180.degree. C. for direct liquid injection. A flow of 100 sccm of
argon gas may be employed as a carrier gas to help deliver the
vapor of the metal-containing precursor to the reaction chamber
during the precursor pulsing. The reaction chamber process pressure
is about 1 Torr. In a typical ALD or CCVD process, the substrate
such as silicon oxide or metal nitride are heated on a heater stage
in a reaction chamber that is exposed to the metal-containing
precursor initially to allow the complex to chemically adsorb onto
the surface of the substrate. An inert gas, such as argon gas,
purges away unadsorbed excess complex from the process chamber.
After sufficient Ar purging, an oxygen source is introduced into
reaction chamber to react with the absorbed surface followed by
another inert gas purge to remove reaction by-products from the
chamber. The process cycle can be repeated to achieve the desired
film thickness.
[0115] In liquid delivery formulations, the precursors of the
present invention may be delivered in neat liquid form, or
alternatively, may be employed in solvent formulations or
compositions comprising same. Thus, in certain embodiments the
precursor formulations may include solvent component(s) of suitable
character as may be desirable and advantageous in a given end use
application to form a film on a substrate.
[0116] The solvent employed in solubilizing the precursor for use
in a deposition process may comprise any compatible solvent or
their mixture including aliphatic hydrocarbons (e.g., hexane,
heptane, octane, and pentane), aromatic hydrocarbons (e.g., benzene
or toluene), ethers, esters, nitriles, alcohols, amines (e.g.,
triethylamine, tert-butylamine), imines and carbodiimides (e.g.,
N,N'-diisopropylcarbodiimide), ketones, aldehydes, amidines,
guanadines, isoureas, and the like. Further examples of suitable
solvent are selected from the group consisting of glyme solvents
having from 1 to 20 ethoxy --(C.sub.2H.sub.4O)-- repeat units;
C.sub.2-C.sub.12 alkanols, organic ethers selected from the group
consisting of dialkyl ethers comprising C.sub.1-C.sub.6 alkyl
moieties, C.sub.4-C.sub.8 cyclic ethers; C.sub.12-C.sub.60 crown
O.sub.4-O.sub.20 ethers wherein the prefixed C.sub.i range is the
number i of carbon atoms in the ether compound and the suffixed
O.sub.i range is the number i of oxygen atoms in the ether
compound; C.sub.6-C.sub.12 aliphatic hydrocarbons; C.sub.6-C.sub.18
aromatic hydrocarbons; organic esters; organic amines, polyamines
and organic amides.
[0117] Another class of solvents that offers advantages is the
organic amide class of the form RCONR'R'' wherein R and R' are
alkyl having from 1-10 carbon atoms and they can be connected to
form a cyclic group (CH.sub.2).sub.n, wherein n is from 4-6,
preferably 5, and R'' is selected from alkyl having from 1 to 4
carbon atoms and cycloalkyl. N-methyl- or N-ethyl- or
N-cyclohexyl-2-pyrrolidinones, N,N-Diethylacetamide, and
N,N-Diethylformamide are examples.
[0118] The utility of specific solvent compositions for particular
precursors may be readily empirically determined, to select an
appropriate single component or multiple component solvent medium
for the liquid delivery vaporization and transport of the specific
metal-enolate precursor that is employed.
[0119] In another embodiment, a direct liquid delivery method can
be employed by dissolving the metal-containing precursor of the
present invention in a suitable solvent or a solvent mixture to
prepare a solution with a molar concentration from 0.01 to 2 M,
depending the solvent or mixed-solvents employed. The solvent
employed herein may comprise any compatible solvents or their
mixture including, but not limited to, aliphatic hydrocarbons,
aromatic hydrocarbons, linear or cyclic ethers, esters, nitriles,
amines, polyamines, and organic amides, preferably a solvent with a
high boiling point, such as mesitylene (b.p. 164.degree. C.) or
N-methyl-2-pyrrolidinone (b.p. 202.degree. C.).
[0120] The method described herein also includes a cyclic
deposition process for the formation of ternary metal oxide films
wherein a plurality of precursors are sequentially introduced into
a deposition chamber, vaporized and deposited on a substrate under
conditions for forming a said ternary metal oxide film.
[0121] In one particular embodiment, the resultant metal oxide
films can be exposed to a post-deposition treatment such as a
plasma treatment to densify the film.
[0122] As mentioned previously, the method described herein may be
used to deposit a metal-containing film on at least a portion of a
substrate. Examples of suitable substrates include but are not
limited to, semiconductor materials such as strontium titanate,
barium strontium titanate, yttrium oxide doped with titanium,
lanthanum oxide doped with titanium, and other lanthanide oxides
doped with titanium,
[0123] The following examples illustrate the method for preparing a
metal-containing precursor of the present invention and are not
intended to limit it in any way.
EXAMPLES
[0124] In the following examples, the GCMS Spectra for the examples
were performed on a Hewlett Packard 5890 Series 11 GC and 5972
series mass selective detector with a HP-5MS. The NMR analyses for
the examples were obtained on a Bruker AMX 500 spectrometer
operating at 500. MHz. Chemical shifts were set from C.sub.6D.sub.6
at 7.16 ppm in .sup.1H and 128.39 parts per million (ppm) in
.sup.13C.
Example 1
Synthesis of
bis(2,2,5,5-tetramethylhex-3-en-3-olato)hexa(ethoxy)di-titanium
[0125] Under a nitrogen atmosphere, 16 ml of 2.5M nBuLi (0.04
moles) were added dropwise to 4.04 g (0.04 moles) of
diisopropylamine in 50 ml of dry teytrahydrofuran cooled to
-60.degree. C. using dry ice. After 30 minutes at -60.degree. C.,
the mixture was allowed to warm to room temperature for 20 minutes
then cooled back to -60.degree. C. 6.24 g (0.04 moles) of
2,2,5,5-tetramethylhexan-3-one dissolved in 80 ml of
tetrahydrofuran were then added dropwise over a 30 minute period,
maintaining -60.degree. C. The mixture was maintained at
-60.degree. C. for an additional 45 minutes then allowed to warm to
room temperature over a 20 minute period. The resulting lithium
enolate was then added over a 20 minute period to 8.72 g (0.04
moles) of tris(ethoxy)monochloro titanium dissolved in 50 ml of
tetrahydrofuran at -60.degree. C. The reaction mixture was then
allowed to warm to room temperature overnight. The solvents were
then removed by vacuum, 250 ml of dry hexane were added to the
resulting crude reaction product, the mixture agitated then
filtered and the hexane removed resulting in a orange-yellow solid.
This product was then vacuum distilled at 120.degree. C. to give
10.7 g (80% yield) of di-titanium
bis(2,2,5,5-tetramethylhex-3-en-3-olato)hexa(ethoxy), characterized
by X-ray diffraction, shown in FIG. 1.
Example 2
Synthesis of
Bis(2,2,5,5-tetramethylhex-3-en-3-olato)(bis(iso-propoxy)titanium
[0126] Under a nitrogen atmosphere, 16 ml of 2.5M nBuLi (0.04
moles) were added dropwise to 4.04 g (0.04 moles) of
diisopropylamine in 50 ml of dry teytrahydrofuran cooled to
-60.degree. C. using dry ice. After 30 minutes at -60.degree. C.,
the mixture was allowed to warm to room temperature for 20 minutes
then cooled back to -60.degree. C. 6.24 g (0.04 moles) of
2,2,5,5-tetramethylhexan-3-one dissolved in 80 ml of
tetrahydrofuran were then added dropwise over a 30 minute period,
maintaining -60.degree. C. The mixture was maintained at
-60.degree. C. for an additional 45 minutes then allowed to warm to
room temperature over a 20 minute period. The resulting lithium
enolate was then added over a 20 minute period to 10.4 g (0.04
moles) of tris(isopropoxy)monochloro titanium dissolved in 50 ml of
tetrahydrofuran at -60.degree. C. The reaction mixture was then
allowed to warm to room temperature and then brought to reflux
overnight. The solvents were then removed by vacuum, 250 ml of dry
hexane were added to the resulting crude reaction product, the
mixture agitated then filtered and the hexane removed resulting in
a orange-yellow solid. This product was then vacuum distilled at
120.degree. C. to give 11.1 g of crude product. This was
redistilled under vacuum up to 115.degree. C. The product that did
not distill over was allowed to cool, forming a crystalline solid,
melting point 34.degree. C., structure proven by X-ray analysis,
shown as FIG. 2. TGA shows (FIG. 3) it is volatile, leaving an
involatile residue of only 0.29% indicating and can be used as a
titanium source in a CVD/ALD process.
Example 3
Tris(2,2,5,5-tetramethylhex-3-en-3-olato)(dimethylamido)titanium
[0127] Under a nitrogen atmosphere, 25.6 ml of 2.5M nBuLi (0.064
moles) were added dropwise to 9.0 ml (0.064 moles) of
diisopropylamine in 75 ml of dry teytrahydrofuran cooled to
-60.degree. C. using dry ice. After 30 minutes at -60.degree. C.,
the mixture was allowed to warm to room temperature for 20 minutes
then cooled back to -60.degree. C. 10.0 g (0.064 moles) of
2,2,5,5-tetramethylhexan-3-one dissolved in 125 ml of
tetrahydrofuran were then added dropwise over a 30 minute period,
maintaining -60.degree. C. The mixture was maintained at
-60.degree. C. for an additional 45 minutes then allowed to warm to
room temperature over a 20 minute period. The resulting lithium
enolate was then slowly added to 2.34 ml (0.021 moles) of titanium
tetrachloride stirred in 75 ml of dry tetrahydrofuran. The
resulting mixture was then refluxed overnight. The mixture was then
allowed to cool to room temperature and 1.1 g (0.021 moles) of
lithium diisopropylamide added as 21.8 g of a 5 wt % suspension in
hexane and the resulting mixture refluxed overnight. The solvents
were removed by vacuum. 250 ml of dry hexane were added to the
resulting crude reaction product, the mixture agitated then
filtered and the hexane removed resulting in 11.6 g of an orange
brown oil. This was then vacuum distilled at 100 mTorr at
180.degree. C. to yield the final product as a waxy orange solid,
melting point 77.3.degree. C., yield 8.5 g (71%)
[0128] TGA showed an involatile residue of only 2.01%. The
combination of low melting point and low TGA residue indicate this
complex is an excellent titanium source for ALD or CVD.
[0129] .sup.1H NMR: (500 MHz, d.sub.8 toluene): .delta.=1.24 (s,
27H), .delta.=1.32 (s, 27H), .delta.=3.27 (s, 6H), .delta.=4.45 (s,
3H).
[0130] Structure proven by X-ray analysis of crystals grown from
hexane, see FIG. 4.
Example 4
Bis(2,2,7,7-tetramethylocta-3,5-dien-3,6-diolato)bis(dimethylamino)titaniu-
m
[0131] Under a nitrogen atmosphere, 14.6 ml of 2.5M nBuLi (0.0364
moles) were added dropwise to 8.4 ml (0.04 moles) of
hexamethyldisilazane in 100 ml of dry hexane cooled to 0.degree. C.
using ice. After 15 minutes 3.25 g (0.0164 moles) of
2,2,7,7-tetramethyl-3,6-octanedione were added dropwise over a 5
minute period leading to the formation of a precipitate of lithium
dienolate. The resulting mixture was stirred an additional 15
minutes and then filtered and the solid rinsed with 2.times.20 ml
of dry hexane after which it was dried by vacuum and dissolved in
25 ml of tetrahydrofuran. A suspension of 37 g of 5 wt % of lithium
diisopropylamide (0.0364 moles) in was then hydrolyzed by the slow
addition of 0.6 g (0.0364 moles) of water in 5 ml of
tetrahydrofuran. After stirring for 15 minutes the solvent and
liberated dimethylamine were condensed under vacuum into a dry
flask containing 3.03 g (0.0364 moles) of titanium tetrachloride
bis(tetrahydrofuran) in 25 ml of tetrahydrofuran. This mixture was
then stirred and the tetrahydrofuran solution of the lithium
dienolate was slowly added at room temperature resulting in a
brilliant deep mauve solution which was then stirred for 2 days at
room temperature. The solvents were then removed by vacuum and the
resulting dark mauve solid was extracted with hexane (500 ml
total). Hexane was then removed by vacuum to yield a dark mauve
solid, yield 1.4 g (32%).
[0132] .sup.1H NMR: (500 MHz, d.sub.8 toluene): .delta.=1.38 (s,
36H), .delta.=1.76 (m, 2H), .delta.=1.95 (d, 12H), .delta.=5.23 (s,
4H).
[0133] Structure proven by X-ray crystallography, see FIG. 6
Example 5
Prophetic
ALD of titanium dioxide by ALD using
bis(2,2,5,5-tetramethylhex-3-en-3-olato)hexa(ethoxy)di-titanium
[0134] The precursor
bis(2,2,5,5-tetramethylhex-3-en-3-olato)hexa(ethoxy)di-titanium is
delivered by pulse bubbling at 100 C. into an ALD reactor at a
chamber pressure of 1 Torr. Oxidation pulses is provided by ozone
from an ozone generator. Using silicon substrates at 300 C, after
100 cycles of precursor/argon purge/ozone/argon purge results in
the deposition of a titanium dioxide film.
Example 6
Prophetic
ALD of titanium dioxide by ALD using
bis(2,2,5,5-tetramethylhex-3-en-3-olato)(bis(iso-propoxy)titanium
[0135] The precursor
bis(2,2,5,5-tetramethylhex-3-en-3-olato)(bis(iso-propoxy)titanium
is delivered by pulse bubbling at 100 C. into an ALD reactor at a
chamber pressure of 1 Torr. Oxidation pulses is provided by ozone
from an ozone generator. Using silicon substrates at 300 C, after
100 cycles of precursor/argon purge/ozone/argon purge results in
the deposition of a titanium dioxide film.
Example 7
Prophetic
ALD of titanium dioxide by ALD using
tris(2,2,5,5-tetramethylhex-3-en-3-olato)(dimethylamido)titanium
[0136] The precursor
tris(2,2,5,5-tetramethylhex-3-en-3-olato)(dimethylamido)titanium is
delivered by pulse bubbling at 100 C. into an ALD reactor at a
chamber pressure of 1 Torr. Oxidation pulses is provided by ozone
from an ozone generator. Using silicon substrates at 300 C, after
100 cycles of precursor/argon purge/ozone/argon purge results in
the deposition of a titanium dioxide film.
[0137] The foregoing examples and description of the preferred
embodiments should be taken as illustrating, rather than as
limiting the present invention as defined by the claims. As will be
readily appreciated, numerous variations and combinations of the
features set forth above can be utilized without departing from the
present invention as set forth in the claims. Such variations are
not regarded as a departure from the spirit and scope of the
invention, and all such variations are intended to be included
within the scope of the following claims.
* * * * *