U.S. patent application number 14/983282 was filed with the patent office on 2016-04-21 for back contact solar cell and fabrication method thereof.
This patent application is currently assigned to LG ELECTRONICS INC.. The applicant listed for this patent is LG ELECTRONICS INC.. Invention is credited to II Hyoung JUNG, Bum Sung KIM, Hwa Nyeon KIM, Jin Ah KIM, Jong Hwan KIM, Ju Hwan YUN.
Application Number | 20160111565 14/983282 |
Document ID | / |
Family ID | 41016274 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160111565 |
Kind Code |
A1 |
KIM; Hwa Nyeon ; et
al. |
April 21, 2016 |
BACK CONTACT SOLAR CELL AND FABRICATION METHOD THEREOF
Abstract
The present invention discloses a back contact solar cell. The
back contact solar cell includes a semiconductor substrate having a
front surface and a rear surface; a first conductive type
semiconductor region having a first conductive type and a second
conductive type semiconductor region having a second conductive
type at an interval on the rear surface of the semiconductor
substrate. Furthermore, the rear surface of the semiconductor
substrate has a texturing structure at the interval between the
first conductive type semiconductor region and the second
conductive type semiconductor region.
Inventors: |
KIM; Hwa Nyeon; (Seoul,
KR) ; YUN; Ju Hwan; (Seoul, KR) ; KIM; Jong
Hwan; (Seoul, KR) ; KIM; Bum Sung; (Seoul,
KR) ; JUNG; II Hyoung; (Seoul, KR) ; KIM; Jin
Ah; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG ELECTRONICS INC. |
Seoul |
|
KR |
|
|
Assignee: |
LG ELECTRONICS INC.
Seoul
KR
|
Family ID: |
41016274 |
Appl. No.: |
14/983282 |
Filed: |
December 29, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12812910 |
Jan 21, 2011 |
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PCT/KR2008/006685 |
Nov 13, 2008 |
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14983282 |
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Current U.S.
Class: |
438/71 ;
438/98 |
Current CPC
Class: |
H01L 31/02363 20130101;
H01L 31/02168 20130101; Y02P 70/50 20151101; H01L 31/02366
20130101; H01L 31/0682 20130101; Y02P 70/521 20151101; H01L 31/1804
20130101; Y02E 10/547 20130101; H01L 31/0236 20130101; H01L
31/022441 20130101 |
International
Class: |
H01L 31/0224 20060101
H01L031/0224; H01L 31/18 20060101 H01L031/18; H01L 31/0236 20060101
H01L031/0236 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 25, 2008 |
KR |
10-2008-0016725 |
Claims
1. A method of making a back contact solar cell, the method
comprising: forming an oxide layer on a rear surface of a
semiconductor substrate; forming a first conductive type
semiconductor region by doping a first dopant material of a first
conductive type; forming a second conductive type semiconductor
region by doping a second dopant material of a second conductive
type; patterning the oxide layer on the rear surface of the
semiconductor substrate to locally remove the oxide layer on the
rear surface at a first location to form a first exposed portion of
the semiconductor substrate to form a first contact between the
first conductive type semiconductor region and a first electrode,
and at a second location to form a second exposed portion of the
semiconductor substrate to form a second contact between the second
conductive type semiconductor region and a second electrode; and
forming the first electrode at the first exposed portion and the
second electrode at the second exposed portion.
2. The method according to claim 1, wherein the first conductive
type is an n-type, and wherein, in the forming the first conductive
type semiconductor region, POCl.sub.3 is used as a source of the
first dopant material.
3. The method according to claim 1, further comprising: forming an
oxide layer on a front surface of the semiconductor substrate.
4. The method according to claim 1, wherein the patterning is
performed using an irradiated laser light.
5. The method according to claim 1, wherein the first dopant
material is an n-type material and the second dopant material is a
p-type material.
6. The method according to claim 1, wherein the forming of oxide
layer is performed as one of a rapid thermal oxidation (RTO) method
performed inside a furnace for rapid thermal processing (RTP); and
a sputtering method using silicon oxide as a target material.
7. The method according to claim 1, wherein a portion of the oxide
layer remains on the rear surface of the semiconductor
substrate.
8. The method according to claim 1, wherein the first conductive
type semiconductor region and the second conductive type
semiconductor region is disposed with an interval on the rear
surface of the semiconductor substrate.
9. The method according to claim 8, wherein the rear surface of the
semiconductor substrate has a texturing structure at the interval
between the first conductive type semiconductor region and the
second conductive type semiconductor region.
10. The method according to claim 9, wherein the rear surface of
the semiconductor substrate further has a portion having a flat
surface, and the flat surface is between the first contact and the
texturing structure, the second contact and the texturing
structure, or both.
11. The method according to claim 10, wherein a width of a portion
of the first electrode is greater than a width of the first
conductive type semiconductor region, or a width of a portion of
the second electrode is greater than a width of the second
conductive type semiconductor region.
12. The method according to claim 9, wherein the rear surface of
the semiconductor substrate has the texturing structure locally to
correspond only to the interval between the first conductive type
semiconductor region and the second conductive type semiconductor
region.
13. The method according to claim 9, wherein the texturing
structure is not formed on at portions of the rear surface of the
semiconductor substrate corresponding to the first conductive type
semiconductor region and the second conductive type semiconductor
region.
14. The method according to claim 1, wherein the oxide layer is
interposed between the first conductive type semiconductor region
and the second conductive type semiconductor region.
15. The method according to claim 9, wherein the oxide layer is
formed on the rear surface of the semiconductor substrate at an
interval between the first conductive type semiconductor region and
the second conductive type semiconductor region, and the oxide
layer has a corresponding texturing structure to the texturing
structure of the semiconductor substrate.
16. A method of making a back contact solar cell, the method
comprising: forming an oxide layer on a rear surface of a
semiconductor substrate; removing at least one portion of the oxide
layer by using a laser to expose the semiconductor substrate;
providing POCl.sub.3 to the exposed portion of the semiconductor
substrate; providing a first dopant material to a first portion on
the semiconductor substrate; providing a second dopant material to
a second portion on the semiconductor substrate; and forming a
first electrode on the first portion and a second electrode on the
second portion.
17. The method of claim 16, further comprising forming a first
conductive type semiconductor region on the first portion and
forming a second conductive type semiconductor region on the second
portion.
18. The method of claim 17, wherein the forming of the first
conductive type semiconductor region and the forming of the second
conductive type semiconductor region are performed by thermally
diffusing the first and second dopant materials respectively into
the first and second conductive type semiconductor regions.
19. The method of claim 17, wherein the first conductive type
semiconductor region is an n-type and the second conductive type
semiconductor region is a p-type.
20. The method according to claim 16, wherein a portion of the
oxide layer remains on the rear surface of the semiconductor
substrate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 12/812,910 filed on Jan. 21, 2011, which is
the national phase of PCT International Application No.
PCT/KR2008/006685 filed on Nov. 13, 2008, which claims the benefit
of Korean Patent Application No. 10-2008-0016725 filed on Feb. 25,
2008. The entire contents of all of the above applications are
hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a fabrication method of a
back contact solar cell, and in particular to a fabrication method
of a back contact solar cell capable of simplifying a fabrication
process thereof and also reducing fabrication costs thereof by
forming a pattern for formation of a p-type semiconductor region
and an n-type semiconductor region on a rear surface of the back
contact solar cell by a laser method to allow a complicated process
such as photolithography to be omitted.
[0004] 2. Discussion of the Related Art
[0005] Recently, due to problems such as a rapid rise in oil
prices, an environmental problem of the earth, exhaustion of fossil
energy, waste treatment in nuclear power generation, position
selection according to construction of a new power plant, etc.,
interest in renewable energy has increased and among others,
research and development for a solar cell, which is a
pollution-free energy source, has actively been progressed.
[0006] The solar cell, which is a device converting light energy
into electrical energy using a photovoltaic effect, is divided into
a silicon solar cell, a thin film solar cell, a dye sensitized
solar cell, and an organic polymer solar cell, etc., according to
type and configuration of materials. Such a solar cell is
independently used as a main power supply in an electronic watch, a
radio, a manless lighthouse, a satellite, a rocket, etc., and is
also used as an auxiliary power supply in connection to a system of
a commercial AC power supply. Recently, due to increase in the
necessity for alternative energy, interest in the solar cell has
increased.
[0007] A structure of a crystalline silicon solar cell firstly used
among these solar cells and being also used to some degree in the
current solar cell market is shown in FIG. 1. Hereinafter, a
fabrication method of a conventional crystalline silicon solar cell
will be described with reference to FIG. 1.
[0008] First, a texturing structure for minimizing reflectance of
incident light is formed on a surface of a p-type silicon substrate
110. Thereafter, an n-type material such as POCl.sub.3 is thermally
diffused onto a whole surface of the substrate 110 to form an
n-type semiconductor layer 120, thereby forming a p-n junction.
[0009] Next, an anti-reflection coating 130 for minimizing the
reflectance is formed on a surface, which is a light-receiving face
in the substrate 110, that is, a surface to which solar light is
incident. Thereafter, rear electrodes 140 such as an aluminum
electrode, etc. are formed on a rear surface of the substrate 110
and at the same time, a rear electric field layer 150 is formed by
thermally processing the rear surface of the n-type semiconductor
layer 120.
[0010] Finally, front electrodes 160 penetrating the
anti-reflection coating 130 to reach to the n-type semiconductor
layer 120 are formed to complete the crystalline silicon solar
cell.
[0011] However, such a crystalline silicon solar cell has a
disadvantage that since there are the front electrodes 160 formed
in a metal finger line form on the surface to which the solar light
is incident, that is, the light-receiving face side, it is
impossible to avoid shadowing.
[0012] More specifically, the metal finger line is formed in a form
protruded on the light-receiving face so that the shadowing is
generated, wherein the shadowing reduces an area to which the solar
light may be incident, thereby having a bad effect on efficiency of
the solar cell.
[0013] For this reason, the crystalline silicon solar cell has a
problem that it is difficult to generate a high efficiency of 18%
or more. In order to solve the problem, a back contact solar cell
has been designed.
[0014] FIGS. 2 to 10 show a fabrication process of a conventional
back contact solar cell. Hereinafter, the fabrication process of
the conventional back contact solar cell will schematically be
described with reference to FIGS. 2 to 10.
[0015] First, as shown in FIG. 2, a cut surface of an n-type
silicon substrate 210 cut in a predetermined size is partially
etched and prepared. Thereafter, as shown in FIG. 3, a texturing
structure for minimizing reflectance of incident light is formed on
at least one of an upper surface or a lower surface of the silicon
substrate 210 using a base solution, etc.
[0016] Thereafter, as shown in FIG. 4, a rear surface of the
substrate 210 is finely polished for planarization.
[0017] Next, as shown in FIG. 5, p-type dopant sources 230 and
n-type dopant sources 250 are printed on the rear surface of the
substrate 210 using a screen printer, etc. Thereafter, as shown in
FIG. 6, the p-type dopant sources 230 and the n-type dopant sources
250 are diffused to form an n-type region and a p-type region,
respectively.
[0018] Next, as shown FIGS. 7 and 8, thermal oxide layers 261 and
263 for surface passivation and an anti-reflection coating 270 made
of silicon nitride SiN.sub.x, etc., are formed on front and rear
surfaces of the substrate 210.
[0019] Next, as shown in FIG. 9, the oxide layer 263 formed on the
rear surface of the substrate 210 is partially removed. This
process is to form rear electrodes, that is, electrodes
electrically contacting the p-type region and the n-type region. In
this process, a photolithography process is used in order to remove
the oxide layer 263.
[0020] More specifically, a photoresist is applied on the oxide
layer 263, and a mask having a pattern corresponding to a region of
the oxide layer 263 to be removed for formation of the rear
electrodes is applied thereon and is exposed so that the oxide
layer 263 is selectively removed.
[0021] After partially removing the oxide layer 263 through this
process, the rear electrodes 271 and 273 electrically connected to
the p-type region and the n-type region are formed, as shown in
FIG. 10, to complete the back contact solar cell.
[0022] The photolithography process is requisite for the
fabrication process of such a conventional contact solar cell. That
is, the rear electrodes have been formed in order to solve the
problem of efficiency deterioration due to the shadowing of the
conventional crystalline silicon solar cell; however, it is
requisite to partially remove the oxide layer 263 in order to form
the rear electrodes and to this end, the photolithography process
should be performed.
[0023] Such a photolithography process is very complicated as well
as causes an increase in process time and fabrication costs,
thereby lowering fabrication efficiency of the back contact solar
cell.
[0024] Therefore, it is very required to develop technology capable
of solving the problem of a low efficiency due to the shadowing and
at the same time, fabricating a back contact solar cell only by a
simplified process.
SUMMARY OF THE INVENTION
[0025] The present invention has been proposed in order to solve
the problem in the prior art as described above. It is an object of
the present invention to provide a fabrication method of a back
contact solar cell capable of obtaining effects such as rise in
efficiency due to minimization of a shadowing effect, which is an
original advantage of the back contact solar cell, reduction in
recombination of electron-hole pairs due to the rear surface
passivation, etc., and at the same time, accomplishing a simplified
fabrication process and a low fabrication costs, by using a laser
method instead of a complicated process such as photolithography,
etc., conventionally used to form a pattern for formation of a
p-type semiconductor region and an n-type semiconductor region
comprised in a rear surface of the back contact solar cell.
[0026] In order to accomplish the above object, the present
invention provides a fabrication method of a back contact solar
cell having a plurality of different conductive type semiconductor
regions on a rear surface of a first conductive type semiconductor
substrate comprising the steps of: forming oxide layers on front
and rear surfaces of the substrate; and removing the oxide layer by
irradiating laser light to the oxide layer formed on the rear
surface of the substrate at predetermined intervals to form a
pattern of the different conductive type semiconductor regions.
[0027] The first conductive type semiconductor substrate may be
changed according to a conductive type of dopant, and is not
necessarily limited to a specific conductive type, but preferably
may be a p-type silicon substrate.
[0028] In the present invention, the fabrication method of the back
contact solar cell may further comprise the step of alternatively
forming a first conductive type semiconductor region and a second
conductive type semiconductor region by diffusing different
conductive type dopants into the pattern formed at the
predetermined intervals. The first conductive type semiconductor
region and the second conductive type semiconductor region may be
an n-type (n+) semiconductor region and a p-type (p+) semiconductor
region, respectively.
[0029] A method forming the n-type semiconductor region is not
specifically limited, but may be any one n-type dopant doping
method selected from a group consisting of an ion implantation
method, a thermal diffusion method, and a phosphorous oxychloride
(POCl.sub.3) diffusion method. More specifically, the n-type
semiconductor region may be formed by a method inserting a p-type
substrate into a high-temperature furnace and injecting an n-type
impurity generation gas at a high concentration thereinto while
heating temperature to 800 or 900.degree. C., wherein the n-type
impurity generation gas may preferably be phosphorous oxychloride
(POCl.sub.3).
[0030] Also, a method forming the p-type semiconductor region is
not specifically limited, but the p-type semiconductor region may
be formed by a screen printing method of a p-type dopant
material.
[0031] The fabrication method of the back contact solar cell of the
present invention may further comprise the step of forming metal
electrodes on each of the first conductive type semiconductor
region and the second conductive type semiconductor region after
forming the first conductive type semiconductor region and the
second conductive type semiconductor region.
[0032] The metal electrode may be formed by, but not necessarily
limited to, a screen printing method.
[0033] In the fabrication method of the back contact solar cell of
the present invention, a laser source used to irradiate the laser
light is not specifically limited, but preferably may be a green
laser source or an Nd/YAG laser source.
[0034] The fabrication method of the back contact solar cell of the
present invention may further comprise the step of forming an
anti-reflection coating on an upper surface of the oxide layer
formed on the front surface of the substrate.
[0035] Also, the front and rear surfaces of the first conductive
semiconductor substrate may have a texturing structure.
[0036] A fabrication method of a back contact solar cell having a
plurality of different conductive type semiconductor regions on a
rear surface of a p-type semiconductor substrate according to one
embodiment of the present invention comprises the steps of: forming
oxide layers on front and rear surfaces of the substrate; forming
n-type semiconductor regions in a pattern in which the oxide layer
is removed by irradiating laser light to the oxide layer formed on
the rear surface of the substrate at predetermined intervals;
forming p-type semiconductor regions in a pattern in which the
oxide layer is removed by irradiating laser light to the oxide
layer between the n-type semiconductor regions at predetermined
intervals from the n-type semiconductor region; and forming metal
electrodes on each of the n-type semiconductor region and the
p-type semiconductor region.
[0037] A back contact solar cell of the present invention
comprises: a first conductive type semiconductor substrate having a
front surface and a rear surface of a texturing structure; an oxide
layer formed on the front surface of the substrate; at least one
first conductive type semiconductor region and second conductive
type semiconductor region alternatively formed at predetermined
intervals on the rear surface of the substrate; an oxide layer
formed on the remaining rear surface of the substrate except for
the first conductive type semiconductor region and the second
conductive type semiconductor region; and electrodes formed on each
of the first conductive type semiconductor region and the second
conductive type semiconductor region.
[0038] The first conductive type semiconductor substrate may be a
p-type silicon substrate, and the first conductive type
semiconductor region and the second conductive type semiconductor
region may be an n-type (n+) semiconductor region and a p-type (P+)
semiconductor region, respectively.
[0039] A resultant formed by oxidation will be sufficient as the
oxide layer; however, the oxide layer preferably is silicon oxide
(SiO.sub.2) formed by rapid thermal oxidation (RTO). Also, the back
contact solar cell may further comprise an anti-reflection coating
on an upper surface of the oxide layer formed on the front surface
of the substrate.
[0040] According to the fabrication method of the back contact
solar cell of the present invention, it is possible to simplify a
fabrication process, reduce fabrication time, and reduce
fabrication costs by using the laser method instead of
photolithography in forming the pattern for formation of the p-type
semiconductor region and the n-type semiconductor region.
[0041] Also, it is possible to obtain effects such as a rise in
efficiency due to minimization of the shadowing effect, which is an
original advantage of the back contact solar cell, a reduction in
recombination of electron-hole pairs due to rear surface
passivation, etc.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The above and other objects, features and advantages of the
present invention will become apparent from the following
description of preferred embodiments given in conjunction with the
accompanying drawings, in which:
[0043] FIG. 1 is a cross-sectional view showing a structure of a
conventional crystalline silicon solar cell;
[0044] FIGS. 2 to 10 are schematic views showing a fabrication
process of a conventional back contact solar cell; and
[0045] FIGS. 11 to 17 are schematic views showing a fabrication
process of a back contact solar cell according to one embodiment of
the present invention.
[0046] Hereinafter, embodiments of the present invention will be
described in detail with reference to accompanying drawings.
DESCRIPTION OF THE EMBODIMENTS
[0047] FIGS. 11 to 17 are schematic views showing a fabrication
process of a back contact solar cell according to one embodiment of
the present invention. Hereinafter, the fabrication process of the
back contact solar cell according to the present invention will be
described with reference to FIGS. 11 to 17.
[0048] First, as shown in FIG. 11, a texturing structure is formed
on at least one of a front surface and a rear surface of a p-type
silicon substrate 310. The texturing structure may usually be
formed in a pyramid shape, etc, and performs a function of
reflecting solar light incident to the solar cell so that maximum
light may be absorbed into an inside of the solar cell, thereby
raising efficiency of the solar cell.
[0049] The texturing structure may be formed by etching using a
known etching method. As an example, the texturing structure may be
formed by immersing the silicon substrate 310 in a basic etching
solution such as tetramethylammonium hydroxide (TMHA), potassium
hydroxide (KOH), or sodium hydroxide (NaOH), etc., to which
surfactant such as isopropyl alcohol (IPA), isopropyl ethanol
(IPE), etc., is added.
[0050] After forming the texturing structure, thermal oxide layers
321 and 323 for surface passivation are formed on the front and
rear surfaces of the silicon substrate 310. The passivation layers
321 and 323 have a role of stabilizing and protecting the surface
and minimizing surface recombination of electron-hole pairs to
increase efficiency of the solar cell.
[0051] These passivation layers 321 and 323 may be thermal oxide
such as silicon oxide (SiO.sub.2), etc., formed by a rapid thermal
oxidation (RTO) scheme performed inside a furnace for rapid thermal
processing (RTP), as described above. Also, the passivation layers
321 and 323 may be formed by a sputtering method using the silicon
oxide (SiO.sub.2) as a target material.
[0052] After forming the passivation layers 321 and 323, a pattern
for diffusing an n-type material is formed on the rear surface of
the silicon substrate 310, as shown in FIG. 12.
[0053] The formation of the pattern is to partially remove the
oxidation layer 323 already formed on the rear surface of the
silicon substrate 310, thereby making it possible to diffuse an
n-type material through the removed portion.
[0054] A process forming the pattern by partially removing the
oxide layer 323 may be performed by irradiating laser light. As a
light source of the irradiated laser light, various light sources
may be used; by way of example, a green laser source with a
wavelength of about 532 nm, an Nd/YAG laser source with a
wavelength of about 1064 nm, etc., may be used.
[0055] After partially removing the oxide layer 323, an n-type
material 330 is diffused into portions at which the oxide layer 323
is removed, as shown in FIG. 13.
[0056] As a method diffusing the n-type material 33, a thermal
diffusion method, etc., may be used. By way of example, a method
performing doping by inserting the p-type silicon substrate 310
into a high-temperature furnace and flowing the n-type material
(for example, POCl.sub.3) into an inside of the furnace may be
used.
[0057] After diffusing the n-type material 330, the oxide layer 323
is removed in order to form a p-type semiconductor region in a
region except for the region into which the n-type material is
diffused, as shown in FIG. 14. At this time, a certain amount of
the oxidation layer 323 is left in a region close to the region
into which the n-type material 330 is diffused in order to insulate
between the region into which the n-type material 330 is diffused
and the p-type semiconductor region.
[0058] At this time, the oxide layer 323 may also be removed by
irradiating green laser light with the wavelength of about 532 nm,
Nd/YAG laser light with the wavelength of about 1064 nm, etc.
[0059] The oxide layer 323 left in order to isolate the region into
which the n-type material is diffused and the p-type semiconductor
region may perform a function of a rear passivation layer of the
back contact solar cell. That is, the remaining oxide layer 323
protects the rear surface of the silicon substrate 310 as well as
prevents rear surface recombination of electron-hole pairs so as to
be able to contribute to improvement in efficiency of the solar
cell.
[0060] After removing all oxide layer 323 except for a certain
amount of the oxide layer 323 for isolating the region into which
the n-type material 330 is diffused and the p-type semiconductor
region among the oxide layer 323 formed on the rear surface of the
silicon substrate 310, the p-type semiconductor region 340 is
formed by printing an aluminum (Al) metal, etc. in a region except
for the region into which the n-type material is diffused, as shown
in FIG. 15. The printing of the aluminum (Al) metal, etc., for
forming the p-type semiconductor region 340 may be performed by a
screen printing method, etc., which is a well-known printing
method.
[0061] In fabrication of the back contact solar cell of the present
invention, since the removal of oxide layer 323 required for
diffusing the n-type material 330 and the removal of the oxide
layer 323 required for forming the p-type semiconductor region 340
are performed by irradiating the laser light, it is possible to
omit a photolithography process requisitely used to remove the
oxide layer on the rear surface of the conventional back contact
solar cell. Since the photolithography process, which is a
complicated and expensive process, may be omitted, it is possible
to simplify the fabrication process of the back contact solar cell
and also reduce fabrication costs.
[0062] After forming the p-type semiconductor region 340, an
anti-reflection coating 370 is formed on an upper surface of the
oxide layer 321 formed on the front surface of the p-type silicon
substrate 310, as shown in FIG. 16. The anti-reflection coating 370
may be deposited using a deposition method such as a plasma
enhanced chemical vapor deposition (PECVD) method, a sputtering
method, or a spin coating method, etc., and be made of a material
such as silicon nitride (SiN.sub.x) or titanium dioxide
(TiO.sub.2), etc. This anti-reflection coating 370 may have a
function of minimizing reflectance of the solar cell and at the
same time, perform a function of a passivation layer. Accordingly,
defects of the back contact solar cell are minimized and
recombination of electron-hole pairs is further reduced, so that
the efficiency of the solar cell may be improved.
[0063] After forming the anti-reflection coating 370, electrodes
are printed on each of the regions into which the n-type material
is diffused and the p-type semiconductor region 340 to form rear
electrodes 390, thereby completing the back contact solar cell, as
shown in FIG. 17. As the electrode 390, a metal with a high
conductivity such as silver (Ag), etc., may be used.
[0064] Although the present invention has been illustrated with
regard to specific details such as specific components, etc,
limited embodiments, and drawings, the specific details such as
specific components, etc, the limited embodiments, and the drawings
are only provided in order to assist overall understanding of the
present invention. The prevent invention is not limited to the
above embodiment, but may be variously modified and altered by
those skilled in the art.
[0065] Therefore, a technical idea of the present invention is not
limited to the above-mentioned embodiment and claims described
below and equivalents thereof are within a scope of the technical
idea of the present invention.
[0066] According to the fabrication method of the back contact
solar cell of the present invention, it is possible to simplify a
fabrication process, reduce fabrication time, and reduce
fabrication costs by using the laser method instead of
photolithography in forming the pattern for formation of the p-type
semiconductor region and the n-type semiconductor region.
[0067] Also, it is possible to obtain effects such as a rise in
efficiency due to minimization of the shadowing effect, which is an
original advantage of the back contact solar cell, a reduction in
recombination of electron-hole pairs due to rear surface
passivation, etc.
* * * * *