U.S. patent application number 15/612440 was filed with the patent office on 2017-12-07 for sensor platform.
The applicant listed for this patent is SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION. Invention is credited to Yoonki HONG, Jong-Ho LEE.
Application Number | 20170350853 15/612440 |
Document ID | / |
Family ID | 60483123 |
Filed Date | 2017-12-07 |
United States Patent
Application |
20170350853 |
Kind Code |
A1 |
LEE; Jong-Ho ; et
al. |
December 7, 2017 |
SENSOR PLATFORM
Abstract
Provided is an FET-type sensor array. In the FET-type sensor
array, a plurality of FET-type sensors are arranged at arbitrary
distances from one reference point, and the same areas of the
FET-type sensors are arranged to face the reference point. The
FET-type sensors includes a control electrode, a floating
electrode, a sensing material layer arranged between the control
electrode and the floating electrode, and source and drain regions
formed on both sides of a lower portion of the floating electrode.
In the FET-type sensor array, through miniaturisation of FET-type
sensors constituting the sensor array and new design of air layers
in the peripheries of micro-heaters built in the sensors and
sensing material layers, power consumption of the micro-heaters can
be reduced. In addition, the sensors can be efficiently arranged to
reduce the area occupied by the sensor array, and the sensing
material can also be heated by the adjacent micro-heaters, so that
the total power consumption can also be reduced.
Inventors: |
LEE; Jong-Ho; (Seoul,
KR) ; HONG; Yoonki; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION |
Seoul |
|
KR |
|
|
Family ID: |
60483123 |
Appl. No.: |
15/612440 |
Filed: |
June 2, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62345194 |
Jun 3, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 27/002 20130101;
G01N 27/4141 20130101; G01N 27/16 20130101; G01N 33/0031 20130101;
H01L 29/788 20130101; H01L 29/42328 20130101 |
International
Class: |
G01N 27/414 20060101
G01N027/414; G01N 33/00 20060101 G01N033/00; H01L 29/423 20060101
H01L029/423; H01L 29/788 20060101 H01L029/788 |
Claims
1. An FET-type sensor array comprising; a plurality of FET-type
sensors which are arranged at arbitrary distances from one
reference point, wherein the FET-type sensor includes: a
semiconductor substrate; a semiconductor body formed to protrude
from the semiconductor substrate; an isolation insulating film
formed on a side surface of the semiconductor body; a gate
insulating film formed on the semiconductor body; a floating
electrode formed on the gate insulating film and the isolation
insulating film; a protective insulating film formed at least on
the floating electrode; a control electrode formed to face and be
horizontally separated from at least one side surface of the
floating electrode; a sensing material layer arranged on the
control electrode and at least horizontally opposing sidewalls of
the floating electrode, the sensing material layer being arranged
to the floating electrode with the protective insulating film
interposed therebetween; and source/drain regions formed in the
semiconductor body with the floating electrode interposed
therebetween, and wherein the same areas of the FET-type sensors
are arranged to face a reference point.
2. The FET-type sensor array according to claim 1, wherein the
sensing material layers lot a plurality of the FET-type sensors are
made of a plurality of sensing materials having different
compositions, and each sensing material is applied to one or more
FET-type sensors.
3. The FET-type sensor array according to claim 1, wherein the
control electrode is formed on the isolation insulating film to
have a specific length and is used as a micro-heater, wherein the
protective insulating film is formed at least on the floating
electrode and the control electrode, and wherein the FET-type
sensor further includes an air layer formed at least below the
isolation insulating film that is in contact with the control
electrode.
4. The FET-type sensor array according to claim 3, wherein the
sensing material layers of a plurality of the FET-type sensors are
made of a plurality of sensing materials having different
compositions, and each sensing material is applied to one or more
FET-type sensors,
5. The FET-type sensor array according to claim 3, wherein the
control electrodes used as the micro-heaters of a plurality of the
FET-type sensors are arranged to be adjacent to each other, and
thus, the sensing material layer in each FET-type sensor is heated
by the control electrode of each FET-type sensor and the control
electrode of the adjacent FET-type sensor, or the control electrode
used as the micro-heater of each FET-type sensor is formed to face
a reference point, so that power consumption is reduced.
6. The FET-type sensor array according to claim 3, wherein the
control electrodes of a plurality of the FET-type sensors are
connected to each other in series or in parallel, or some of the
control electrodes are connected to each other in series and the
others of the control electrodes are connected to each other in
parallel, and wherein line widths of the control electrodes used as
the micro-heaters are equal to each ether or the line width is
changed depending on each FET-type sensor.
7. The FET-type sensor array according to claim 3, wherein the
FET-type sensor further includes: metal wires which are in electric
contact with the control electrodes; and a plurality of contact
holes which are formed between the control electrodes and the metal
wires, and wherein the line widths of the sensing material layers
and the control electrodes in the peripheries thereof in the sensor
array are formed to be smaller than the line widths of the control
electrodes in the remaining areas.
8. The FET-type sensor array according to claim 3, wherein the
FET-type sensor further includes an undercut pattern for forming an
air layer, and wherein the undercut pattern is formed to have one
of shapes including a circle, an ellipse, a square, a square having
rounded corners, a rectangle, a rectangle having rounded corners or
formed to have one of shapes including an ellipse, a rectangle, and
a rectangle having rounded corners and include one or more regions
that are bent at arbitrary angles in the middle.
9. The FET-type sensor array according to claim 1, wherein the
control electrode is formed to have a specific length is used as a
micro-heater, and wherein the FET-type sensor further includes an
air layer formed at least below art isolation insulating film which
is in contact, with the control electrode.
10. The FET-type sensor array according to claim 9, wherein the
sensing material layers of a plurality of the FET-type sensors are
made of a plurality of sensing materials having different
compositions, and each sensing material is applied to one or more
FET-type sensors.
11. The FET-type sensor array according to claim 9, wherein the
control electrodes used as the micro-heaters of a plurality of the
FET-type sensors are arranged to be adjacent to each other, and
thus, the sensing material layer in each FET-type sensor is heated
by the control electrode of each FET-type sensor and the control
electrode of the adjacent FET-type sensor, or the control electrode
used as the micro-heater of each FET-type sensor is formed to face
a reference point, so that power consumption is reduced.
12. The FET-type sensor array according to claim 9, wherein the
control electrodes of a plurality of the FET-type sensors are
connected to each other in series or in parallel, or some of the
control electrodes are connected to each other in series and the
others of the control electrodes are connected to each other in
parallel, and where line widths of the control electrodes used as
the micro-heaters are equal to each other or the line width is
changed depending on each FET-type sensor.
13. The FET-type sensor array according to claim 9, wherein the
FET-type sensor includes: metal, wires which are in electric
contact with the control electrodes; and a plurality of contact
holes which are formed between the control electrodes and the metal
wires, wherein the line widths of the sensing material layers and
the control electrodes in the peripheries thereof in the sensor
array are formed to be smaller than the line widths of the control
electrodes in the remaining areas, and wherein, in the case where
the control electrode that is in contact with the sensing material
layer is made of metal, a material having a thermal conductivity
lower than that of a metal is connected through contact holes
provided at both ends of the control electrode and arranged with a
predetermined length, and a metal wire is connected through contact
holes provided at both ends of the material having low thermal
conductivity.
14. The FET-type sensor array according to claim 9, wherein the
FET-type sensor further includes an undercut pattern for forming an
air layer, and wherein the undercut pattern is formed to have one
of shapes including a circle, an ellipse, a square, a square having
rounded corners, a rectangle, a rectangle having rounded corners or
formed to have one of shapes including an ellipse, a rectangle, and
a rectangle having rounded corners and include one or two regions
that are bent at arbitrary angles in the middle.
15. The FET-type sensor array according to claim 1, wherein the
FET-type sensor further includes: a micro-heater formed with a
predetermined length on the isolation insulating film to face and
be horizontally separated from at least one side surface of the
floating electrode; and an air layer formed at least below the
isolation insulating film that is in contact with the micro-heater,
wherein the protective insulating film is formed at least on the
floating electrode and the micro-heater, and wherein the
micro-heater of each FET-type sensor is formed to face the
reference point.
16. The FET-type sensor array according to claim 15, wherein the
sensing material layers of a plurality of the FET-type sensors are
made of a plurality of sensing materials having different
compositions, and each sensing material is applied to one or more
FET-type sensors.
17. The FET-type sensor array according to claim 15, wherein the
micro-heaters of a plurality of the FET-type sensors are arranged
to be adjacent to each other, and thus, the sensing material layer
in each FET-type sensor is heated by the micro-heater of each
FET-type sensor and the micro-heater of the adjacent. PET- type
sensor, so that power consumption is reduced.
18. The FET-type sensor array according to claim 15, wherein the
micro-heaters of a plurality of the FET-type sensors are connected
to each other in series or in parallel, or some of the
micro-healers are connected to each other in series and the others
of the micro-heaters are connected to each other in parallel, and
wherein the line widths of the micro-heaters are equal to each
other or the line width is changed depending on each FET-type
sensor.
19. The FET-type sensor array according to claim 15, wherein the
FET-type sensor further includes: a metal wire which, is in
electric contact with the micro-heater; and a plurality of contact
holes which are formed between, the micro-heater and the metal
wire, wherein the line widths of the sensing material layers and
the micro-heaters in the peripheries thereof in the sensor array
are formed to he smaller than the line widths of the micro-heaters
in the remaining areas, and wherein, in the case where the control
electrode that is in contact with the sensing material layer is
made of metal, a material having a thermal conductivity lower than
that of a metal is connected through contact holes provided at both
ends of the control electrode and arranged with a predetermined
length, and a metal wire is connected through contact holes
provided at both ends of the material having low thermal
conductivity.
20. The FET-type sensor array according to claim 15, wherein the
FET-type sensor further includes an undercut pattern for forming an
air layer, and wherein the undercut pattern is formed to have one
of shapes including a circle, an ellipse, a square, a square having
rounded corners, a rectangle, a rectangle having rounded corners or
formed to have one of shapes including an ellipse, a rectangle, and
a rectangle having rounded corners and include one or more regions
that are bent at arbitrary angles in the middle.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to an FET-type sensor array,
and more particularly, to an FET-type sensor array including
silicon-based MOSFET (metal-oxide-semiconductor field-effect
transistor) type sensors having a floating electrode formed in a
horizontal direction on a control electrode, an FET-type sensor
array including FET-type sensors having a built-in micro-heater,
and a method of manufacturing the same capable of ensuring thermal
and mechanical stability and greatly reducing size and total power
consumption through creative and efficient arrangement of the
sensors and being applied to sensors for sensing various gases.
2. Description of the Related Art
[0002] In recent years, gas sensors having various structures have
been developed to sense various gases including harmful gases which
cause environmental problems. As the gas sensors, there may be
exemplified resistance-type gas sensors having a semiconductor as a
sensing material, gas sensors using an infrared ray, optical gas
sensors, and FET-type gas sensors. Particularly, among these gas
sensors, the FET-type gas sensors capable of being miniaturized,
operating with lower power, and being incorporated with CMOS
circuits such as low noise amplifying circuits have been
increasingly studied.
[0003] In the field of the gas sensor array, most of the gas sensor
arrays that are used to distinguish, various gases by using a
pattern recognition circuit or software are mainly based on
resistance-type gas sensors in the related art on which different
sensing materials are deposited. On the other hand, during the gas
sensing, gas sensing characteristics are changed depending on a
change of external environment such as a concentration of gas and
an ambient temperature as well as a gas type. Particularly, the
ambient temperature is a factor affecting gas sensitivity and gas
reaction and recovery speeds.
[0004] A gas sensor has the optimum temperature at which the
sensitivity of the gas sensor is maximized for each gas sensing
material and each kind of gas to be sensed. In general, the higher
the ambient temperature, the faster the gas reaction and the
recovery speeds. In the field of the gas sensors array in the
related art, studies of improving gas sensing characteristics by
introducing various types of heaters have been made.
[0005] The FET-type sensors can foe applied mainly to gas sensing.
Besides, the FET-type sensors can be applied to other types of
sensing (for example, fine particle sensing, heavy metal sensing,
and the like).
[0006] US Patent Application Publication No. US 2006/0187279
A1(Patent Document 1) discloses a gas sensor array where
resistance-type gas sensors having a semi conductive metal oxide as
a sensing material are arranged at a constant interval. Each gas
sensor is provided with a micro-heater that can control an ambient
temperature during gas sensing and a temperature sensor that can
sense the ambient temperature. However, the gas sensors
constituting the gas sensor array are of a resistance-type, and the
distance between the gas sensors is considerably large, so that the
total area is large.
[0007] In addition, since the gas sensor has a relatively large
resistance-type structure, power consumption is increased to heat,
a sensing material layer of the gas sensor.
[0008] Korean Patent Laid-Open Publication No. 2013-0052528 (Patent
Document 2) illustrates a basic structure and advantages of an
FET-type gas sensor constituting a gas sensor array proposed by the
invention. The FET-type gas sensor disclosed in Patent Document 2
has a basic structure where a control electrode and a floating
electrode are formed in a horizontal direction, a sensing material
layer is located therebetween, and a micro-heater and an air layer
are arranged near the control electrode. On the basis of the
structure, the FET-type gas sensor uses a change in work function,
a change in capacitance according to a change in dielectric
constant, charge generation/extinction, electromotive force
generation, and the like as sensing mechanisms.
[0009] The FET-type gas sensor disclosed in Patent Document 2 can
significantly reduce power consumption in comparison with sensors
in the related art and can sense various types of gases accurately
by changing the sensing mechanisms even if the same gas sensing
material is used. In addition, since the sensing material is formed
in the final stage of device fabrication, there is no problem in
that contamination problems occur. In the FET-type gas sensor
having the above-mentioned structure disclosed in Patent Document
2, it is possible to solve the problems of the FET-type gas sensor
having the floating electrode and the control electrode and the
sensing material layer formed in the vertical direction in the
related art. Namely, it is possible to solve the problems such as a
low coupling ratio between a control electrode and a floating
electrode due to a parasitic capacitance component, low sensing
sensitivity, and large power consumption, and high manufacturing
cost caused from complexity of processes.
[0010] However, in the above-mentioned patents, the structures and
the expected effect of the arrangement, of the gas sensors are very
briefly described.
[0011] Accordingly, the present invention proposes specific and
efficient arrangement of a gas sensor array including FET-type gas
sensors having a horizontal floating electrode and efficient design
of a micro-heater and an air layer built, in each gas sensor. The
array structure according to the invent ion can significantly
reduce total area and total power consumption in comparison with
the gas sensor arrays in the related art.
[0012] Korean Patent Laid-Open Publication No. 2014-010633 (Patent
Document 3) discloses a three-dimensional Fin-FET-type gas sensor.
The three-dimensional Fin-FET-type gas sensor is formed so that a
floating electrode is formed to surround a semiconductor body
protruding in a FIN shape to enlarge a width of a channel to
increase a drain current, so that the Fin-FET-type gas sensor has
an advantage of increasing the sensitivity of the sensor.
[0013] Non-Patent Document 1 is "Micro-machined gas sensor array
based on metal film micro-heater," Yaowu Mo et al., Sensors and
Actuators B: Chemical, pp. 175-181, No. 79, 2001. The gas sensor
array introduced in Non-Patent Document 1 is configured with eight
resistance-type gas sensors, and each gas sensor has a micro-heater
in which titanium (Ti) and platinum (Pt) are deposited in this
order. As a sensing material, tin oxide (SnO.sub.2) is used, and it
was found that the sensing material has a selectivity for ethanol
(C.sub.2H.sub.5OH). Unlike the studies in the related art, an air
layer for reducing loss of heat of the micro-heater is formed not
from a backside of a substrate, but the air layer is formed through
anisotropic silicon etching of the silicon from a top side of the
substrate to improve thermal characteristics. On the other hand,
since the gas sensor has a resistance-type structure, the area
occupied by the sensing material layer is 50 .mu.m.times.50 .mu.m
in order to solve the problem of production yield. Therefore, e
power consumption of the micro-heater for heating the sensing
material layer and the size of the gas sensor array including eight
gas sensors are very large, 2 mm.times.4 mm.
[0014] Non-Patent Document 2 is "Room temperature multiplexed gas
sensing using chemical-sensitive 3.5-nm-thin silicon transistors",
Hossain Mohammad Fahad et al., Science Advances, e1602557, No. 3,
2017. In Non-Patent Document 2, a gas sensor constituting a gas
sensor array has an FET-type structure where a silicon substrate
having a bundle of thin silicon channels is as a control electrode,
and the silicon channels are doped with metal substances such as
palladium (Pd), nickel (Ni), and gold (Au) to analyse sensing
characteristics of various gases. In addition, micro-heaters where
chrome (Cr) and gold (Au) are sequentially deposited are formed in
the periphery of the gas sensors, and thus, desorption rates of
gases adsorbed to the sensing material layers are improved by
heating the micro-heaters. However, there is no air layer for
preventing loss of heat generated by the micro-heaters, and the
micro-headers occupies a large area around the gas sensors, and
thus, the power consumption is unnecessarily large. In addition,
the size of the gas sensor array is also very large.
[0015] Therefore, development of a newly designed gas sensor array
capable of solving the problems of the gas sensor arrays in the
related has been required.
SUMMARY OF THE INVENTION
[0016] The invention is proposed to solve disadvantages of a
sensor-array including a plurality of resistance-type sensors or
FET-type sensors in the related art such as an unnecessarily large
size of the sensor array, large power consumption of micro-heaters,
and high manufacturing cost caused from complexity of processes.
The invention is to provide an efficient arrangement of an FET-type
sensor having a horizontal floating electrode constituting a sensor
array and an efficient structure of a micro-heater and an air
layer.
[0017] According to an aspect of the invention, there is provided
an FET-type sensor array including a plurality of FET-type sensors
which are arranged at arbitrary distances from one reference point,
wherein the FET-type sensor includes: a semiconductor substrate; a
semiconductor body formed to protrude from the semiconductor
substrate; an isolation insulating film formed on a side surface of
the semiconductor body; a gate insulating film formed on the
semiconductor body; a floating electrode formed on the gate
insulating film and the isolation insulating film; a protective
insulating film formed at least on the floating electrode; a
control electrode formed to face and be horizontally separated from
at least one side surface of the floating electrode; a sensing
material layer arranged on the control electrode and at least
horizontally opposing sidewalls of the floating electrode, the
sensing material layer being arranged to the floating electrode
with the protective insulating film interposed therebetween; and
source/drain regions formed in the semiconductor body with the
floating electrode interposed therebetween, and wherein the same
areas of the FET-type sensors are arranged to face a reference
point.
[0018] In the FET-type sensor array according to the above aspect,
the sensing material layers of a plurality of the FET-type sensors
may be made of a plurality of sensing materials having different
compositions, and each sensing material may be applied to one or
two or more FET-type sensors.
[0019] In the FET-type sensor array according to the above aspect,
the control electrode may be formed on the isolation insulating
film to have a specific length and be used as a micro-heater, the
protective insulating film may be formed at least on the floating
electrode and the control electrode, and the FET-type sensor may
further include an air layer formed at least below the isolation
insulating film that is in contact with the control electrode.
[0020] In the FET-type sensor array according to the above aspects,
the control electrodes used as the micro-heaters of a plurality of
the FET-type sensors may be arranged to be adjacent to each other,
and thus, the sensing material layer in each FET-type sensor is
heated by the control electrode of each FET-type sensor and the
control electrode of the adjacent FET-type sensor, or the control
electrode used as the micro-heater of each FET-type sensor is
formed to face a reference point, so that power consumption is
reduced.
[0021] In the FET-type sensor array according to the above aspect,
the control electrodes of a plurality of the FET-type sensors may
be connected to each other in series or in parallel, or some of the
control electrodes may be connected to each other in series and the
others of the control electrodes are connected to each other in
parallel; and line widths of the control electrodes used as the
micro-heaters may be equal to each other or the line width may be
changed depending on each FET-type sensor.
[0022] In the FET-type sensor array according to the above aspect,
the line widths of the sensing material layers and the control
electrodes in the peripheries thereof in the sensor array are
formed to be smaller than the line widths of the control electrodes
in the remaining areas, and the FET-type sensor may further include
metal wires which are in electric contact with the control
electrodes and a plurality of contact holes which are formed
between the control electrodes and the metal wires.
[0023] In the FET-type sensor array according to the above aspect,
the FET-type sensor may further include an undercut pattern for
forming the air layer, and the undercut pattern may be formed to
have one of shapes including a circle, an ellipse, a square, a
square having rounded corners, a rectangle, a rectangle having
rounded corners or maybe formed to have one of shapes including an
ellipse, a rectangle, and a rectangle having rounded corners and
include one or two regions that are bent at arbitrary angles in the
middle.
[0024] The sensor array according to the invention basically
includes a plurality of FET-type sensors having a floating
electrode formed in an upper portion of a semiconductor body in
which a channel is formed and a sensing material layer and a
control electrode arranged in a horizontal direction thereof. At
this time, the semiconductor body is formed to protrude from the
semiconductor substrate, and an isolation insulating film is formed
on a side surface of the semiconductor body. A micro-heater
isolated by an isolation insulating film may be included in the
periphery of the control electrode and the sensing material layer
of the FET-type sensor, and Anisotropic etching of the Isolation
insulating film and isotropic etching of the semiconductor
substrate may be sequentially performed to provide an air layer
below the micro-heater.
[0025] The FET-type sensors constituting the sensor array according
to the invention has micro-heaters made of a metal or
polycrystalline silicon having high thermal conductivity and high
electric conductivity in the periphery of the control electrode and
the sensing material layer. In this case, the micro-heater is
arranged in the horizontal direction with respect to the floating
electrode, and in the case where the micro-heater and the floating
electrode are formed with the same material, the micro-heater can
be formed without additional mask and process.
[0026] In the FET-type sensor constituting the sensor array
according to the invention, after forming the control electrode,
the isolation insulating film and the semiconductor substrate in
the periphery of the sensing material layer are etched by
additionally using a mask to form an air layer below the
micro-heater. At this time, the air layer may be locally formed
only in the periphery of the sensing material layer, so that, it is
possible to minimize loss of heat of the micro-heater and to reduce
power consumption.
[0027] The sensor array according to the invention may have
independent micro-heaters or micro-heaters connected as a single
micro-heater. When the micro-heaters are arranged in a plurality of
the sensors in the sensor array, the micro-heaters of the sensors
are arranged to be close to each other, and thus, it is possible to
provide a structure that can be sufficiently heated by the
micro-heaters of the adjacent sensors as well as the micro-heaters
built in the sensors, so that it is possible to obtain the effect
of reducing power consumption.
[0028] The line widths of the micro-heaters built in the FET-type
sensors constituting the sensor array according to the invention
can be arbitrarily adjusted. Since the maximum sensitivity of a
sensing material applied to a sensor may be different depending on
a heater temperature, by selecting the line width of the
micro-heater suitable for the optimum temperature of reaction of
each sensing material, it is possible to increase the sensitivity
and to reduce power consumption.
[0029] In the FET-type sensors constituting the sensor array
according to the invention, the line widths of the micro-heaters
arranged in the regions other than the sensing material layers and
the peripheries thereof are increased, so that it is possible to
minimize the heat generation, and air layers are formed, so that it
is possible to reduce loss of heat and power consumption.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is an exemplary equivalent circuit diagram
illustrating a sensor array where a plurality of FET-type sensors
are arranged in rows and columns as an example of a sensor array in
the related art;
[0031] FIGS. 2A to 2D illustrate an FET-type sensor having a
horizontal floating electrode in the related art, FIG. 2A is a plan
view, FIG. 2B is across-sectional view taken along line A-A' in
FIG. 2A, FIG. 2C is a cross-sectional view taken along line B-B',
and FIG. 2D is a cross-sectional view of a three-dimensional
Fin-FET-type sensor as a modified form of FIG. 2B;
[0032] FIG. 3 is an exemplary equivalent circuit diagram
illustrating a sensor array where a plurality of FET-type sensors
including a micro-heater and an air layer are arranged in rows and
columns as an example of a sensor array in the related art;
[0033] FIGS. 4A to 4D illustrate an FET-type sensor in the related
art as a modified form of the sensor illustrated in FIG. 2A, FIG.
4A is a plan view, FIG. 4B is across-sectional view taken along
line A-A' in FIG. 4A, FIG. 4C is a cross-sectional view taken along
line B-B', and FIG. 4D is a cross-sectional view of a
three-dimensional Fin-PET-type sensor as a modified form of FIG.
4B;
[0034] FIGS. 5A to 5D illustrate examples of a sensor arrangement
method of the sensor array according to the invention, FIG. 5A is
an equivalent circuit diagram illustrating a case where sensors are
arranged on a circle to be separated from each other at an
arbitrary angle, FIG. 5B is an equivalent circuit diagram
illustrating a case where sensors are arranged on an ellipse, FIG.
5C is an equivalent circuit diagram illustrating a case where
sensors are arranged on a rectangle, and FIG. 5D is an equivalent
circuit diagram illustrating a case where the same areas of the
FET-type sensors arranged on a rectangle face a reference point and
are deviated by arbitrary angles from lines connecting the
reference point and the centers of the FET-type sensors;
[0035] FIGS. 6A to 6G illustrate examples of a sensor arrangement
method of the sensor array according to the invention, FIG. 6A is
an equivalent circuit diagram illustrating a case where sensors
having a built-in micro-heater are arranged on a circle to be
separated from each other at an arbitrary angle, FIG. 6B is an
equivalent circuit diagram illustrating a case where sensors having
a built-in micro-heater are arranged on an ellipse and the heaters
are connected in series, FIG. 6C is an equivalent circuit diagram
illustrating a case where sensors having a built-in micro-heater
are arranged on an ellipse and the heaters are arranged in
parallel, FIG. 6D is an equivalent circuit diagram illustrating a
case where sensors having a built-in micro-heater are arranged on a
rectangle and the heaters are connected in series, FIG. 6E is an
equivalent circuit diagram illustrating a case where sensors having
a built-in micro-heater are arranged on a rectangle and the heaters
are arranged in parallel, FIG. 6F is an equivalent circuit diagram
illustrating a case where sensors having a built-in micro-heater
are arranged on a rectangle, the heaters are connected in series,
and the heaters face a reference point and are deviated by
arbitrary angles from lines connecting the reference point and the
centers of the FET-type sensors, and FIG. 6G is an equivalent
circuit diagram illustrating a case where sensors having a built-in
micro-heater are arranged on a rectangle, the heaters are connected
in parallel, and the heaters face a reference point and are
deviated by arbitrary angles from lines connecting the reference
point and the centers of the FET-type sensors;
[0036] FIGS. 7A and 7B illustrate FET-type sensors having a
horizontal floating electrode in the related art constituting a
sensor array according to the invention, FIG. 7A is a plan view
illustrating a case where a source electrode and one-end electrode
of a micro-heater are separated, and FIG. 7B is a plan view
illustrating a case where a source electrode and one-end electrode
of a micro-heater are shared;
[0037] FIGS., 8A and 8B illustrate modified examples of the sensors
illustrated in FIGS. 7A and 7B, respectively, and are plan views
illustrating cases where line widths of the micro-heaters arranged
in the regions other than the sensing material layers and the
peripheries thereof are increased;
[0038] FIGS. 9A and 9B illustrate modified examples of the sensors
illustrated, in FIGS. 8A and 8B, respectively, and are plan views
illustrating cases where the number of contact holes of the
micro-heater is increased;
[0039] FIGS. 10A and 10B illustrate modified examples of the
sensors illustrated in FIGS. 9A and 9B, respectively, and are plan
views illustrating cases where materials having a thermal
conductivity lower than that of a metal are connected to have a
certain length through contact holes provided at both ends of a
control electrode which is made of a metal and metal wires are
connected through contact holes provided at both ends of each
material having low thermal conductivity;
[0040] FIGS. 11A and 11B illustrate modified examples of the
sensors illustrated in FIGS. 10A and 10B, respectively, and are
plan views illustrating cases where undercut patterns are formed as
close as possible to a micro-heater and anchors are formed between
the patterns; and
[0041] FIGS. 12A and 12B illustrate examples of a sensor
arrangement method of a sensor array according to the invention
having a structure in which sensors are arranged as close as
possible so as to be sufficiently heated by the micro-heaters of
the adjacent sensors, FIG. 12A is a plan view illustrating a case
where the sensor array is configured with sensors having the same
sensing material and micro-heaters having the same line width, and
FIG. 12B is a plan view illustrating a case where the sensor array
is configured with sensors having different sensing materials and
micro-heaters having different line widths.
DETAILED DESCRIPTION OF THE INVENTION
[0042] As illustrated in FIG. 1, unlike the related art. where
sensors are arranged in arbitrary intervals of rows or/and columns,
a sensor array according to a first embodiment of the invention is
configured to include a plurality of FET-type sensors SO arranged
at arbitrary distances from one reference point, and the same area
630 (for
[0043] example, a control electrode) of each FET-type sensor 80 is
formed to face the reference point. The same area may be a control
electrode or may be a control electrode that can be used as a
micro-heater.
[0044] The FET-type sensor SO is an FET-type sensor 80 having a
horizontal floating electrode 300 disclosed in Patent Documents 2
and 3. The FET-type sensors 80 include sensors illustrated in FIGS.
2A to 2D where a change in dielectric constant of a sensing
material layer 40 according to presence or absence of a
to-be-sensed material is used as an operation sensing mechanism or
a change in work function is used as an operation sensing
mechanism.
[0045] In particular FIG. 2D illustrates a structure of a
three-dimensional Fin-FET-type sensor disclosed in Patent Document
3. The three-dimensional Fin-FET-type sensor is configured to
include a semiconductor substrate 100, a semiconductor body 110
formed to protrude from the semiconductor substrate 100, an
isolation insulating film 200 formed on a side surface of the
semiconductor body 110 and the semiconductor substrate 100, a gate
insulating film 210 formed on the semiconductor body 110, a
floating electrode 300 formed on the gate insulating film 210 and
the isolation insulating film 200, a control electrode 310 formed
on the isolation insulating film 200 to face and be horizontally
separated from at least one side surface of the floating electrode
300, a sensing material layer 40 formed between the control elect
rode 310 and the floating electrode 300, and source/drain regions
formed in the semiconductor body 110 with the floating gate 300
interposed therebetween, wherein the isolation insulating film 200
is formed on a lower side surface of the semiconductor body 110
such that the semiconductor body 110 protrudes, and the floating
elect rode 300 is formed, to surround, the semiconductor body 110
protruding on the isolation insulating film 200 with the gate
insulating film 210 interposed therebetween. The floating electrode
300 is formed to surround the semiconductor body 110 protruding in
a FIN shape, and thus, the width of the channel is increased, so
that a drain current is increased. Therefore, it is possible to
improve the sensitivity of the sensor.
[0046] In the FET-type sensors 80, in the case where the
cross-sectional structures (the cross-sectional structures taken
along line A-A') of the FET-type sensors 80 are different even
though the same material is used to form the sensing material
layers 40, the operation sensing mechanisms are different, and
thus, the sensing materials may be different. On the contrary, in
the case where the sensing material layers 40 of the FET-type
sensors are different even though the cross-sectional structures of
the FET-type sensors 80 are the same, the operation sensing
mechanisms are different, and thus, the sensing materials may be
different.
[0047] The FET-type sensor array according to the first embodiment
of the invention includes two or more FET-type sensors SO having a
change in capacitance caused from a change in dielectric constant
or a change in work function as a operation sensing mechanism and
having at least one or more sensing materials.
[0048] Even in the case where the sensing mechanisms are applied to
the same sensing material layer 40, the sensing mechanisms may has
different sensing characteristics (referred to as sensing
fingerprints) for a specific material to be sensed. Therefore,
without using a large number of sensing materials, it is possible
to accurately sense the types and the concentrations of materials
to be sensed.
[0049] In the FET-type sensor array according to the first
embodiment of the invention, one or more sensors which are at least
one or more of resistance-type and capacitance-type sensors may be
arranged to be adjacent to the FET-type sensor 80,
[0050] As illustrated in FIG. 3, unlike the related art where
sensors having a built-in micro-heater are arranged in arbitrary
intervals of rows or/and columns, a sensor array according to a
second embodiment of the invention is configured to include a
plurality of FET-type sensors 80 having a horizontal floating
electrode 300, a built-in heater 500, and an air layer 600 formed
in a semiconductor substrate ICQ at the lower end of an isolation
insulating film 200 in a region including a sensing material layer
40, the FET-type sensors are arranged at arbitrary distances from
one reference point, and the same areas 630 (for example, control
electrodes) of the FET-type sensors 80 are formed to face the
reference point. The same area may be a control elect rode or may
be a control electrode that can be used as a micro-heater.
[0051] The FET-type sensors 80 constituting the sensor array
according to the embodiment include the FET-type sensors 80
disclosed in Patent Documents 2 and 3. In particular, as
illustrated in FIGS. 4A to 4D, the FET-type sensors include a
sensor having a micro-heater 50 and an air layer 600 having a
change in dielectric constant of a sensing material layer 40
according to presence or absence of a to-be-sensed material as a
operation sensing mechanism. Besides, the FET-type sensors include
a sensor having a change in work function as a operation sensing
mechanism. In the sensor having the operation sensing mechanism, a
micro-heater 50 may be operated in common with the control
electrode 310 or operated separately from the control electrode
310.
[0052] In particular, FIG. 4D illustrates a structure of a
three-dimensional Fin-FET-type sensor disclosed in Patent Document
3. As described, in the first embodiment, a floating electrode 300
is formed to surround a semiconductor body 110 protruding in a FIN
shape to enlarge a width of a channel to increase a drain current,
so that the Fin-FET-type gas sensor has an advantage of increasing
the sensitivity of the sensor.
[0053] In the FET-type sensors 80, in the case where the
cross-sectional structures (the cross-sectional structures taken
along line A-A') of the FET-type sensors 80 are different even
though the same material is used to form the sensing material
layers 40, the operation sensing mechanisms are different, and
thus, the sensing materials may be different. On the contrary, in
the case where the sensing material layers 40 of the FET-type
sensors are different even though the cross-sectional structures of
the FET-type sensors 80 are the same, the operation sensing
mechanisms are different, and thus, the sensing materials may be
different.
[0054] The FET-type sensor array according to the second embodiment
of the invention includes two or more FET-type sensors 80 having a
change in capacitance caused from a change in dielectric constant
or a change in work function as an operation sensing mechanism and
having at least one or more sensing materials.
[0055] Even in the case where the sensing mechanisms are applied to
the same sensing material layer 40, the sensing mechanisms may has
different sensing characteristics (referred to as sensing
fingerprints) for a specific material to be sensed. Therefore,
without using a large number of sensing materials, it is possible
to accurately sense the types and the concentrations of materials
to be sensed.
[0056] In the FET-type sensor array according to the second
embodiment of the invention, one or more sensors which are at least
one or more of resistance-type and capacitance-type sensors may be
arranged to be adjacent to the FET-type sensor 80. The
resistance-type or capacitance-type sensor in the related art
includes a micro-heater 50 separated by an insulating film 200 at
the lower end thereof and an air layer 600 formed in a
semiconductor substrate 100 at the lower end of an isolation
insulating film 200 to surround the sensing material layer 40.
[0057] A sensor array according to a third embodiment of the
invention is an example of the sensor array according to the first
embodiment of the invention. As illustrated in FIG. 5A, a plurality
of the FET-type sensors 80 are arranged in a shape of a circle
having a certain radius from the reference point, and the same
areas 630 of the FET-type sensors 80 are arranged to face the
reference point.
[0058] A sensor array according to a fourth embodiment of the
invention is an example of the sensor array according to the first
embodiment of the invention. As illustrated in FIG. 5B, a plurality
of the FET-type sensors 80 are arranged in a shape of an ellipse,
and the same areas 630 of the FET-type sensors 80 are arranged to
face the reference point.
[0059] A sensor array according to a fifth embodiment of the
invention is an example of the sensor array according to the first
embodiment of the invention.
[0060] As illustrated in FIG. 5C, a plurality of the FET-type
sensors 80 are arranged in a rectangular shape, and the same areas
630 of the FET-type sensors 80 are arranged to face the reference
point.
[0061] A sensor array according to a sixth embodiment of the
invention is an example of the sensor array according to the first
embodiment of the invention. As illustrated in FIG. 5D, a plurality
of the FIT-type sensors 80 are arranged in a rectangular shape. The
same areas 630 of the FET-type sensors 80 are arranged to face the
reference point and to be deviated by arbitrary angles from lines
connecting the reference point and the centers of the FET-type
sensors 80. The angle .theta. between the line connecting the
reference point and the center of the FET-type sensor 80 and the
line connecting the center of the same area 630 and the center of
the FET-type sensor 80 satisfies
0.degree.=<.theta.<90.degree..
[0062] A sensor array according to a seventh embodiment of the
invention is an example of the sensor array according to the second
embodiment of the invention. As illustrated in FIG. 6A, a plurality
of the FET-type sensors 80 are arranged in a shape of a circle
having a certain radius from the reference point, and the
micro-heaters 50 of the FET-type sensors 80 are arranged to face
the reference point.
[0063] A sensor array according to an eighth embodiment of the
invention is an example of the sensor array according to the second
embodiment of the invention. As illustrated in FIGS. 6B and 6G, a
plurality of the FET-type sensors 80 are arranged in a shape of an
ellipse, and the micro-heaters 50 of the FET-type sensors 80 are
arranged to face the reference point. FIG. 6B illustrates an
example where the micro-heaters 50 are connected in series, one
terminal of each micro-heaters 50 is applied with a heater voltage
V.sub.H, and the other terminal thereof is connected to the ground.
FIG. 6C illustrates an example where the micro-heaters 50 are
connected in parallel, one terminal of each micro-heaters 50 is
applied with a heater voltage the other terminal thereof is
connected to the ground, and the ground terminals of the
micro-heaters 50 are shared as one,
[0064] A sensor array according to a ninth embodiment of the
invention is an example of the sensor array according to the second
embodiment of the invention. As illustrated in FIGS. 6D and 6E, a
plurality of the FET-type sensors are arranged in a shape of a
rectangle, and the micro-heaters 50 of the FET-type sensors 80 are
arranged to face the reference point. FIG. 6D illustrates an
example where the micro-heaters 50 are connected in series, one
terminal of each micro-heaters 50 is applied with a heater voltage
V.sub.H, and the other terminal thereof is connected to the ground,
FIG. 6E illustrates an example where the micro-heaters 50 are
connected in parallel, one terminal of each micro-heaters 50 is
applied with a heater voltage V.sub.H, the other terminal thereof
is connected to the ground, and the ground terminals of the
micro-heaters 50 are shared as one.
[0065] A sensor array according to a tenth embodiment of the
invention is an example of the sensor array according to the second
embodiment of the invention. As illustrated in FIGS. 6F and 6G, a
plurality of the FET-type sensors 80 are arranged in a rectangular
shape, the micro-heaters 50 of the FET-type sensors 80 are arranged
to face the reference point and to be deviated by arbitrary angles
from lines connecting the reference point and the centers of the
FET-type sensors 80. The angle .theta. between the line connecting
the reference point and the center of the FET-type sensor 80 and
the line connecting the center of the micro-heater 50 and the
center of the FET-type sensor 80 satisfies
0.degree.=<.theta.<90.degree.. FIG. 6F illustrates an example
where the micro-heaters 50 are connected in series, one terminal of
each micro-heaters 50 is applied with a heater voltage V.sub.H, and
the other terminal thereof is connected to the ground. FIG. 6G
illustrates an example where the micro-heaters 50 are connected in
parallel, one terminal of each micro-heaters 50 is applied with a
heater voltage V.sub.H, the other terminal thereof is connected to
the ground, and the ground terminals of the micro-beaters 50 are
shared as one.
[0066] In the sensor arrangement method of the sensor arrays
according to the first to tenth embodiments, in comparison with the
sensor array including sensors having micro-heaters in the related
art where the sensors are arranged in rows or/and columns, the
total area occupied by the sensor array is small, and the
micro-heaters 50 built in the sensors are arranged to be close to
each other, and thus, the sensing material layers 40 can be heated
by the adjacent micro-heaters 50. Therefore, there is an advantage
in that the total power consumption can also be reduced.
[0067] In the sensor arrays according to the first to sixth
embodiments, the control electrode 310, the micro-heater 50, the
source/drain electrode 320, the active region 120, and other
regions constituting the FET-type sensor 80 are included in the
same area 630 of the FET-type sensor 80.
[0068] A sensor has the optimum temperature at which the
sensitivity of the sensor is maximized for each sensing material
and each material to be sensed. Therefore, in the case where two or
more different sensing materials are applied to each of the sensor
arrays according to the second and seventh to tenth embodiments,
the line widths of the micro-heaters 50 built in the sensors may be
designed differently according to the optimum temperatures of
reaction of the sensing materials, so that the resistance can be
different.
[0069] In the sensor arrays according to the second and seventh to
tenth embodiments illustrated in FIGS. 6A to 6G, combinations of
the resistance values R.sub.1 to R.sub.n of the micro-heaters 50
are available as follows. All the resistance values are equal to
each other (R.sub.1=R.sub.2=R.sub.3=. . . R.sub.n) all the
resistance values are different from each other
(R.sub.1.noteq.R.sub.2.noteq.R.sub.3.noteq.. . . R.sub.n); and some
of the resistance values are equal to each other and the others are
different from each other (R.sub.1=R.sub.2=. . .
R.sub.n-1.noteq.R.sub.n,
R.sub.1=R.sub.2=R.sub.n-2.noteq.R.sub.n-1R.sub.n).
[0070] In the sensor arrays according to the second and seventh to
tenth embodiments, all the micro-heaters 50 built in a plurality of
the sensors may be connected in series or in parallel, or an
arbitrary number of some of the micro-heaters 50 built in a
plurality of the sensors may be connected in series or in
parallel.
[0071] In the sensor arrays according to the second and seventh to
tenth embodiments, in the FET-type sensor including the
micro-heater 50 operated separately from the control electrode 310,
the source electrode 320 of the FET-type sensor the one end of the
micro-heater 50 built in each FET-type sensor may be separated as
illustrated in FIG. 7A or may be shared with one common electrode
330 as illustrated in FIG. 7B.
[0072] As illustrated in FIGS. 8A and 8B, in the sensor arrays
according to the second and seventh to tenth embodiments, the line
widths of the sensing material layers 40 of FET-type sensors and
the line widths of the micro-heaters 50 in the peripheries of the
sensing material layers 40 are configured to be larger than the
line widths of the micro-heaters 50 arranged in the regions other
than the sensing material layers 40 and the peripheries of the
sensing material layers 40, and thus, the heat generated is
reduced, so that it is possible to reduce loss of heat.
[0073] As illustrated in FIGS. 9A and 9B, in the sensor arrays
according to the second and seventh to tenth embodiments, in order
to prevent the micro-heaters 50 from being physically disconnected
and destructed by the heat generated from the contact holes 70 for
electrically connecting the micro-heaters 50 and the metal wires
311, the number of contact holes 70 is configured to be
sufficiently large, and thus, the total contact area is increased,
so that it is possible to improve the mechanical stability.
[0074] As illustrated in FIGS. 10A and 10B, in the sensor arrays
according to the second and seventh to tenth embodiments, in the
case where the control electrode 310 is a metal, the material 90
having a thermal conductivity lower than that of the metal is
connected to a region of the control electrode 310 through the
contact hole 70 and arranged with a predetermined length, and the
metal wire 311 is connected through the contact hole 70 provided at
the end of the material 90 having low thermal conductivity. As the
material 90 having a thermal conductivity lower than that of the
metal, there may be exemplified polysilicon. The material 90 having
low thermal conductivity is additionally arranged between, the
control electrode 310 made of a metal and the metal wire 311, so
that there is an advantage in that loss of heat generated from the
micro-heaters 50 through the metal wire 311 can be reduced.
[0075] In this case, since the two connection portions are
electrically connected through the contact hole 70, there is no
problem in gating the control electrode 310 for the operation of
the sensor.
[0076] In the sensor arrays according to the second and seventh to
tenth embodiments, the region of the air layer 600 functioning to
reduce the loss of heat of the micro-heater 50 built in each
FET-type sensor always includes the sensing material layer 40. The
formation process for the air layer 600 is performed by
anisotropically etching the isolation insulating film 200 below the
undercut pattern 610 by dry etching or wet etching using a gas such
as CF.sub.4, and subsequently by isotropically etching the
semiconductor substrate 100 below the isolation insulating film 200
by dry etching or wet etching using a gas such as SF.sub.6.
[0077] The undercut pattern 610 is an open pattern and may be
formed by selecting one of shapes including a circular, an ellipse,
a square, a square having rounded corners, a rectangle, a rectangle
having rounded corners or may be formed by selecting one of shapes
including an ellipse, a rectangle, and a rectangle having rounded
corners and including at least one region that is bent at an
arbitrary angle in the middle. In particular, as illustrated in
FIGS. 11A and 11B, the width of the undercut pattern 610 is
configured to be sufficiently thin so that, when the sensing
material layer 40 is formed by a method such as Inkjet printing,
the amount of sensing material that is lost through the air layer
600 is reduced and the sensing material is well deposited between
the floating electrode 300 and the floating electrode 300. Namely,
it is possible to obtain the effect of increasing the sensor
production yield. The undercut pattern 610 is designed to be
arranged as close as possible to the micro-heater 50, so that the
active region 120 of the sensor is not damaged while the
semiconductor substrate 100 is etched to form, the air layer 600.
Therefore, it is possible to obtain the effect, of ensuring
mechanical stability. Finally, an anchor 620 between the undercut
pattern 610 and another adjacent, pattern, is allowed to remain, so
that the sensor can be prevented from collapsing toward the
semiconductor substrate 100 after the etching of the air layer
600.
[0078] As illustrated in FIGS. 11A and 11B, the undercut patterns
610 are formed in the peripheries of the control, electrodes 310
arranged in the regions other than the sensing material layers 40
and the peripheries thereof, between the floating electrode 300 and
the active region 120, and in the peripheries of the portions where
the micro-heaters 50 and the metal wires 311 are connected to the
contact holes 70, and thus the loss of heat of the micro-heater 50
is minimized.
[0079] As illustrated in FIGS. 12A and 12B, in the sensor array
according to the fifth embodiment of the invention, two sensors of
the sensor array according to the second embodiment are included,
the two sensors are formed as close as possible, and the undercut
pattern 610 and the anchor 620 for mechanical stability of the
sensor array are included between the two sensors, FIG. 12A
illustrates the sensor array to which the same sensing material is
applied, and the micro-heaters 50 have the same line width. FIG.
12B illustrates the sensor array to which different sensing
materials are applied, and the micro-heaters 50 have different line
widths.
[0080] As illustrated in FIGS. 5A to 11B, other features of the
sensor array according to the fifth embodiment include all the
features described in the second and seventh to tenth
embodiments.
[0081] A sensor array according to the invention can be implemented
by simple processes and can be easily combined with existing CMOS
processes, so that industrial applicability is high.
[0082] In particular, the sensor array according to the invention
has a higher degree of integration than that of a sensor array
developed in the related art, production yield is high,
manufacturing cost is low, the sensor array can be driven with low
power, and the sensor array can be usefully applied for various
sensor fields of gas sensors, chemical and biological sensors, and
the like.
[0083] While the: present invention has been particularly
illustrated, and described, with reference to exemplary embodiments
thereof, it should be understood by the skilled in the art that the
invention is not limited to the disclosed embodiments, but various
modifications and applications not illustrated in the above
description can be made without departing from the spirit of the
invention. In addition, differences relating to the modifications
and applications should be construed as being included within the
scope of the invention as set forth in the appended claims.
* * * * *