KR20100094326A - Method for fabricating solar cell applications using inductively coupled plasma chemical vapor deposition - Google Patents

Abstract

PURPOSE: A method for fabricating a solar cell through inductively coupled plasma chemical vapor deposition is provided to achieve a micro-crystallized intrinsic layer of a solar cell. CONSTITUTION: A method for fabricating a solar cell through inductively coupled plasma chemical vapor deposition comprises steps of: forming an intrinsic layer of a solar cell using an inductively coupled plasma chemical vapor deposition apparatus which uses a mixed gas including hydrogen gas and silane gas. The solar cell includes a first electrode(210), a first type layer(220), the intrinsic layer(230), a second type layer(240), and a second electrode(250).

Description

Method for fabricating solar cell applications using inductively coupled plasma chemical vapor deposition {Method for fabricating solar cell applications using inductively coupled plasma chemical vapor deposition}

The present invention relates to a solar cell manufacturing method using an inductively coupled plasma chemical vapor deposition method.

Currently, the obligation to reduce greenhouse gases under the Climate Change Convention is accelerating, and the CO2 market is being activated accordingly, which is drawing attention in the renewable energy field.

The solar cell, which is a representative renewable energy field, is a system for producing electricity using solar light, an infinite clean energy source, and a solar cell that directly converts light into electricity is at its core.

Currently, more than 90% of solar cells that are commercially available are bulk-based silicon solar cells, which are affected by silicon supply and demand, and are complicated by high temperature-centric processes, which makes it difficult to thin, thin or low temperature processes.

An object of the present invention is to provide a solar cell manufacturing method using an inductively coupled plasma chemical vapor deposition method.

Another object of the present invention is to provide a P layer forming method of a solar cell.

Another object of the present invention is to provide a method for forming a hydrogenated intrinsic layer of a solar cell.

Yet another object of the present invention is to provide a method for forming a microcrystalline intrinsic layer of a solar cell.

In order to achieve the above object, according to an aspect of the present invention, in manufacturing a solar cell comprising a first electrode, a first type layer, an intrinsic layer, a second type layer and a second electrode, hydrogen (H2) gas and silane And forming an intrinsic layer formed of a hydrogenated amorphous silicon thin film using an inductively coupled plasma chemical vapor deposition apparatus using a mixed gas containing a (SiH 4) gas, wherein the mixed gas includes the hydrogen gas and A solar cell manufacturing method is provided, characterized in that the hydrogen gas to silane gas ratio (H2 / SiH4 ratio) of the silane gas is 8 to 10.

The intrinsic layer forming step has a process pressure of 70 to 90 mtorr, a process power of 200 to 300 W, and a process temperature of 250 to 350 degrees.

The solar cell manufacturing method includes: a first type silicon substrate preparing step of preparing a first type silicon substrate before the intrinsic layer forming step; And a first electrode forming step of forming the first electrode on the back surface of the first type silicon substrate. After the intrinsic layer forming step, a second type forming the second type layer is formed on the intrinsic layer. step; And a second electrode forming step of forming a second electrode on the second type layer.

The first electrode is made of Ag, and the second type layer is formed of a hydrogenated second type amorphous silicon layer, and the second electrode is patterned on the transparent electrode layer and the transparent cathode layer formed on the second type layer. Made of aluminum electrode.

The solar cell manufacturing method: a transparent substrate preparation step of preparing a transparent substrate before the intrinsic layer forming step; A first electrode forming step of forming the first electrode on the transparent substrate; And a second type layer forming step of forming the second type layer on the first electrode. The first type layer forming step of forming the first type layer on the intrinsic layer after the intrinsic layer forming step. And a second electrode forming step of forming the second electrode on the first type layer.

A buffer layer forming step of forming a buffer layer between the second type layer forming step and the intrinsic layer forming step, and between the first type layer forming step and the second electrode forming step, a transparent electrode layer on the first type layer It includes forming a transparent electrode layer to form a.

The first electrode is made of a TCO layer, and the second electrode is made of aluminum.

In order to achieve the above object, according to another aspect of the present invention, in manufacturing a solar cell including a first electrode, a first type layer, an intrinsic layer, a second type layer and a second electrode, hydrogen (H2) gas, silane A second layer for forming the second type layer made of an amorphous silicon carbide thin film using an inductively coupled plasma chemical vapor deposition apparatus using a mixed gas containing a (SiH 4) gas, a diborene (B 2 H 6) gas, and an ethylene (C 2 H 4) gas And forming a die layer, wherein the ethylene gas is ethylene gas 60% diluted with hydrogen gas, the diborene gas is diborene gas 97% diluted with hydrogen gas, and the ethylene gas is 1 in the mixed gas. It is included in the 1.2%, the diborene gas is provided with a solar cell manufacturing method, characterized in that contained in 6 to 6.5% in the mixed gas.

The solar cell manufacturing method includes: a first type silicon substrate preparing step of preparing a first type silicon substrate before the second type layer forming step; A first electrode forming step of forming the first electrode on a rear surface of the first type silicon substrate; And an intrinsic layer forming step of forming the intrinsic layer on the entire surface of the first type silicon substrate. After the second type layer forming step, a second electrode is formed to form a second electrode on the second type layer. It includes; step.

The first electrode is made of Ag, the intrinsic layer is made of a hydrogenated amorphous silicon layer, and the second electrode is made of a transparent electrode layer formed on the second type layer and a patterned aluminum electrode formed on the transparent electrode layer. .

The solar cell manufacturing method: a transparent substrate preparation step of preparing a transparent substrate before the second type layer forming step; And a first electrode forming step of forming the first electrode on the transparent substrate. The intrinsic layer forming step of forming the intrinsic layer on the second type layer after the second type layer forming step. A first type layer forming step of forming the first type layer on the intrinsic layer; And a second electrode forming step of forming the second electrode on the first type layer.

A buffer layer forming step of forming a buffer layer between the second type layer forming step and the intrinsic layer forming step, and between the first type layer forming step and the second electrode forming step, a transparent electrode layer on the first type layer It includes forming a transparent electrode layer to form a.

The first electrode is made of a TCO layer, and the second electrode is made of aluminum.

In order to achieve the above object, according to another aspect of the present invention, in manufacturing a solar cell comprising a first electrode, a second type layer, an intrinsic layer, a first type layer and a second electrode, hydrogen (H2) gas and By using an inductively coupled plasma chemical vapor deposition apparatus using a mixed gas containing a silane (SiH4) gas, any one of the second type layer, the intrinsic layer and the first type layer is formed to be made of a crystallized silicon layer, The mixed gas has a silane gas ratio (SiH 4 / (SiH 4 + H 2)) of 0.016 to 0.02 is provided a solar cell manufacturing method.

The inductively coupled plasma chemical vapor deposition apparatus uses a process power of 1150 to 1250W.

The first type layer may be formed of a crystallized silicon layer using a mixed gas including a phosphine (P2H3) gas, but using a mixed gas containing 0.075 to 0.1% of phosphine gas to the silane gas.

The second type layer may be formed of a crystallized silicon layer using a mixed gas including a diborene gas, but using a mixed gas containing 0.1 to 0.5% of a diborene gas to the silane gas.

The solar cell manufacturing method comprises: a first type silicon substrate preparing step of preparing a first type silicon substrate; A first electrode forming step of forming the first electrode on a rear surface of the first type silicon substrate; And forming an intrinsic layer on the entire surface of the first type silicon substrate. A second type layer forming step of forming the second type layer on the intrinsic layer; And a second electrode forming step of forming a second electrode on the second type layer.

The first electrode is made of Ag, and the second electrode is made of a transparent electrode layer formed on the second type layer and a patterned aluminum electrode formed on the transparent electrode layer.

The solar cell manufacturing method: preparing a transparent substrate for preparing a transparent substrate; A first electrode forming step of forming the first electrode on the transparent substrate; A second type layer forming step of forming the second type layer on the first electrode; An intrinsic layer forming step of forming the intrinsic layer on the second type layer; A first type layer forming step of forming the first type layer on the intrinsic layer; And a second electrode forming step of forming the second electrode on the first type layer.

A buffer layer forming step of forming a buffer layer between the second type layer forming step and the intrinsic layer forming step, and between the first type layer forming step and the second electrode forming step, a transparent electrode layer on the first type layer It includes forming a transparent electrode layer to form a.

The first electrode is made of a TCO layer, and the second electrode is made of aluminum.

According to the configuration of the present invention can achieve all the objects of the present invention described above. Specifically, according to the present invention, there is an effect of providing a solar cell manufacturing method using an inductively coupled plasma chemical vapor deposition method.

Moreover, according to this invention, there exists an effect which provides the P layer formation method of a solar cell.

Moreover, according to this invention, there exists an effect of providing the method of forming the hydrogenation intrinsic layer of a solar cell.

Moreover, according to this invention, there exists an effect of providing the method of forming the microcrystallized intrinsic layer of a solar cell.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram illustrating a schematic configuration of an inductively coupled plasma chemical vapor deposition apparatus used in a solar cell manufacturing method according to embodiments of the present invention.

Referring to FIG. 1, an inductively coupled plasma chemical vapor deposition apparatus 100 used in a solar cell manufacturing method according to embodiments of the present invention includes a chamber 110 and an antenna. (antenna) 120, a power supply unit 130, a shower head 140, and a susceptor 150.

The chamber 110 includes an insulating plate 112, a door 114, and an exhaust port 116.

The chamber 110 serves to spatially separate the inside and the outside of the chamber 110 so that the inside of the chamber 110 maintains a vacuum state.

The insulating plate 112 is provided at an upper end of the chamber 110.

The insulating plate 112 insulates the antenna 120 from the chamber 110 and transmits an electromagnetic field generated by the antenna 120 to the inside of the chamber 110.

The door 114 is provided to charge or withdraw the substrate 60 into the chamber 110.

The exhaust port 116 is connected to a vacuum pump (not shown) to exhaust gas and the like from the chamber 110 to exhaust the chamber 110 to a predetermined vacuum state or to maintain a constant vacuum state. do.

The antenna 120 serves to generate a high density plasma in the chamber 110 by the power supplied from the power supply unit 130.

The antenna 120 is provided while the coil is wound in a helical shape, and is provided on the insulating plate 112 of the chamber 110.

The power supply unit 140 supplies power to the antenna 120 and the susceptor 150.

In particular, the power supply unit 140 applies RF of 13.5 MHz to the antenna 120 to generate a high density plasma in the chamber 110.

The shower head 140 receives a gas from the gas supply unit 142 provided outside the chamber 110 to uniformly supply the inside of the chamber 110.

The shower head 140 also serves to uniformly mix different kinds of gases supplied to the shower head 140 to form a uniformly mixed mixed gas.

The susceptor 160 supports the substrate 160.

Although not shown in detail in FIG. 1, the susceptor 160 may include a heating member for heating the substrate 160 to a predetermined temperature and a cooling member for cooling the substrate 160. have.

The susceptor 160 is provided at a position where a distance between the substrate 160 and the shower head 140 is a predetermined interval, preferably 23 cm.

2 is a cross-sectional view showing an embodiment of a solar cell manufactured by a solar cell manufacturing method according to an embodiment of the present invention.

Referring to FIG. 2, the solar cell 200 manufactured by the solar cell manufacturing method according to an embodiment of the present invention may include a first electrode 210, a first type silicon substrate 220, and an intrinsic layer 230. ), The second type layer 240, and the second electrode 250.

In this case, the first type silicon substrate 220 may be an N type silicon substrate or a P type silicon substrate.

In addition, the second type layer 240 is a P type layer when the first type silicon substrate 220 is an N type silicon substrate, and an N type when the first type silicon substrate 220 is a P type silicon substrate. It may be a layer.

In the present embodiment, it is assumed that the first type silicon substrate 220 is an N type silicon substrate, and the second type layer 240 is a P type layer. That is, it is assumed that the first type is N type and the second type is P type.

In this case, the second electrode 250 includes a transparent electrode layer 252 and a metal electrode 254.

The solar cell 200 includes the first electrode 210 on the rear surface of the first type silicon substrate 220 around the first type silicon substrate 220, and the first type silicon substrate 220. ), The intrinsic layer 230, the second type layer 240, and the second electrode 250 are sequentially stacked.

The first electrode 210 is a rear electrode provided on the rear surface of the first type silicon substrate 220 and is preferably made of a conductive material, preferably Ag.

The first electrode 210 is made of a thickness of 0.3 to 0.8㎛, preferably 0.5㎛.

The first type silicon substrate 220 is formed of a silicon substrate doped with a first type impurity, precisely a first type, that is, a single crystal substrate doped with a first type impurity.

The first type silicon substrate 220 has a thickness of 300 to 1000 μm, preferably 650 μm.

The intrinsic layer 230 may be provided as a hydrogenated amorphous silicon layer that is not doped with impurities, that is, an I a-Si: H layer. In addition, the intrinsic layer 230 may be provided as a hydrogenated microcrystalline silicon layer that is not doped with impurities, that is, an I μc-Si: H layer.

When the intrinsic layer 230 is the I a-Si: H layer, the intrinsic layer 230 may have a thickness of 3 to 5 nm, preferably 5 nm. In addition, when the intrinsic layer 230 is the I μc-Si: H layer, the intrinsic layer 230 may have a thickness of 0.5 to 2 μm, preferably 1 μm.

The second type layer 230 may be formed of a hydrogenated amorphous carbide silicon layer doped with impurities of the second type, that is, a second type a-SiC: H layer. In addition, the second type layer 230 may be formed of a hydrogenated amorphous silicon layer, that is, a P a-Si: H layer doped with a second type impurity.

When the second type layer 230 is formed of the second type a-SiC: H layer, the second type layer 230 may have a thickness of 10 to 20 nm, preferably 12 nm. In addition, when the second type layer 230 is formed of the second type a-Si: H layer, the second type layer 230 may have a thickness of 11 to 12 nm, preferably 12 nm.

The transparent electrode layer 252 of the second electrode 250 may include a transparent conducting oxide (TCO), for example, zinc oxide (ZnO), aluminum zinc oxide (AZO), indium tin oxide (ITO), and SnO 2, which are doped with aluminum. It may be made of a transparent conductive oxide such as: F.

The transparent electrode layer 252 of the second electrode 250 may be provided with a thickness of 100 to 200 nm, preferably 120 nm.

The metal electrode 254 of the second electrode 250 is provided on the transparent electrode layer 252 and is formed of a patterned metal electrode 254.

The metal electrode 254 is made of a conductive material such as aluminum.

The metal electrode 254 is made of a thickness of 0.2 to 1㎛, preferably 0.5㎛.

3 is a cross-sectional view showing another embodiment of a solar cell manufactured by a solar cell manufacturing method according to another embodiment of the present invention.

Referring to Figure 3, the solar cell 300 manufactured by the solar cell manufacturing method according to another embodiment of the present invention is a transparent substrate 310, the first electrode 320, the second type layer 330, The buffer layer 340, the intrinsic layer 350, the first type layer 360, the transparent electrode layer 370, and the second electrode 380 are included.

The solar cell 300 includes the first electrode 320, the second type layer 330, the buffer layer 340, the intrinsic layer 350, the first type layer 360, and the transparent electrode layer on the transparent substrate 310. 370 and the second electrode 380 are sequentially stacked.

The transparent substrate 310 may be provided as a substrate made of an insulator material while transmitting light such as a glass substrate or a plastic substrate.

The first electrode 320 may be made of a transparent conductive oxide such as TCO, for example, ZnO, AZO, ITO, and SnO 2: F, which is a conductive material while transmitting light.

The first electrode 320 may be provided in a form in which irregularities are formed on a surface thereof by a texture process.

The second type layer 330 may be formed of a hydrogenated amorphous silicon carbide layer doped with P-type impurities, that is, a second type a-SiC: H layer. In addition, the second type layer 330 may be formed of a hydrogenated amorphous silicon layer doped with a second type impurity, that is, a second type a-Si: H layer.

When the second type layer 330 is formed of the second type a-SiC: H layer, the second type layer 330 may have a thickness of 10 to 20 nm, preferably 12 nm. In addition, when the second type layer 330 is formed of the second type a-Si: H layer, the second type layer 330 may have a thickness of 11 to 12 nm, preferably 12 nm.

The buffer layer 340 is provided as a buffer between the second type layer 330 and the intrinsic layer 340, and is formed of a hydrogenated amorphous silicon layer doped with a second type, that is, a second type a-Si: H layer. .

The buffer layer 340 has a thickness of 2 to 5nm, preferably 3nm.

The intrinsic layer 350 may be provided as a hydrogenated amorphous silicon layer that is not doped with impurities, that is, an I a-Si: H layer. In addition, the intrinsic layer 350 may be provided as a hydrogenated microcrystalline silicon layer that is not doped with impurities, that is, an I μc-Si: H layer.

When the intrinsic layer 350 is the I a-Si: H layer, the intrinsic layer 350 may have a thickness of 3 to 5 nm, preferably 5 nm. In addition, when the intrinsic layer 350 is the I μc-Si: H layer, the intrinsic layer 350 may have a thickness of 0.5 to 2 μm, preferably 1 μm.

The first type layer 360 may be formed of hydrogenated amorphous silicon doped with first type impurities, that is, a first type a-Si: H layer. In addition, the first type layer 360 may be formed of hydrogenated fine crystallized silicon doped with first type impurities, that is, first type μc-Si: H.

The first type layer 360 has a thickness of 20 to 60 nm, preferably 40 nm.

The transparent electrode layer 370 may be made of a transparent conductive oxide such as TCO, for example, ZnO, AZO, ITO, and SnO 2: F, which is a conductive material while transmitting light.

The transparent electrode layer 370 has a thickness of 100 to 200 nm, preferably 120 nm.

The second electrode 380 is made of a conductive material such as aluminum.

4 is a flowchart illustrating a process sequence of a solar cell manufacturing method according to an embodiment of the present invention.

Referring to FIG. 4, the solar cell manufacturing method according to an exemplary embodiment of the present invention may include preparing a first type silicon substrate (S410), forming a first electrode (S420), forming an intrinsic layer (S430), A second type layer forming step S440 and a second electrode forming step S450 are included.

At this time, the solar cell manufacturing method according to an embodiment of the present invention will be described a solar cell manufacturing method based on the solar cell 200 described with reference to FIG.

The first type silicon substrate preparing step (S410) is a step of preparing the first type silicon substrate 220.

The first type silicon substrate 220 may be a single crystal silicon substrate grown by a CZchralski method.

In this case, the first type of silicon preparation step (S410) includes cleaning the first type silicon substrate 220 and removing an oxide layer.

The type 1 silicon substrate 220 is washed with a solution of sulfuric acid and hydrogen peroxide mixed at 4: 1 for 10 minutes in a solution maintained at 120 ° C. for 10 minutes, and subjected to a BOE (Buffered Oxide Etchant) for about 10 seconds. The oxide film removing process of dipping removes the oxide film.

In addition, the preparing of the first type silicon substrate (S410) includes a drying process of drying the first type silicon substrate 220. That is, a drying process for removing moisture adsorbed to the first type silicon substrate 220 in the cleaning process and the oxide film removing process is performed. The drying process may be a process in which the first type silicon substrate 220 is charged to a vacuum chamber or the like and heated at 200 ° C. for about 2 hours in a state where oxygen is removed.

The first electrode forming step (S420) is a step of forming the first electrode 210 by depositing a conductive material, that is, Ag or a metal on the back surface of the first type silicon substrate 220.

The conductive material, for example, Ag, may be deposited by using physical vapor deposition such as an evaporation method and a sputtering method.

The intrinsic layer forming step (S430) is a step of forming an intrinsic silicon layer containing no impurities of the first type and the second type on the entire surface of the first type silicon substrate 220.

The intrinsic layer forming step (S430) may be formed using the inductively coupled plasma chemical vapor deposition apparatus 100 described with reference to FIG. 1, or may include a chemical vapor phase such as plasma enhanced chemical vapor deposition (Plasma Enhanced Chemical Vapor Deposition). It can also be formed using a vapor deposition apparatus.

In the present embodiment, a description will be given based on a method of forming the intrinsic layer 230 using the inductively coupled plasma chemical vapor deposition apparatus 100.

The intrinsic layer 230 may be formed by using a mixed gas including hydrogen (H 2) gas and silane (SiH 4) gas by using the inductively coupled plasma chemical vapor deposition apparatus 100.

The mixed gas uses a mixed gas having a hydrogen gas to silane gas ratio (H 2 / SiH 4 ratio) of 8 to 10 of the hydrogen gas and the silane gas.

In addition, the intrinsic layer forming step S430 of forming the intrinsic layer 230 has a process pressure of 70 to 90 mtorr, a process power of 200 to 300 W, and a process temperature of 250 to 350 degrees.

Experimental Examples 1 to 3 below are experiments for selecting an optimal process condition for forming the intrinsic layer 230 using the inductively coupled plasma chemical vapor deposition apparatus 100.

Experimental Example 1

5 is a graph showing changes in thickness and surface roughness of an intrinsic layer according to a hydrogen gas to silane gas ratio of a mixed gas.

6 is a graph showing the thickness and surface roughness of the intrinsic layer with the change of the process pressure.

Referring to FIGS. 5 and 6, the hydrogen gas to silane gas ratio and the process pressure of the mixed gas are changed to show the thickness and surface roughness of the intrinsic layer 230, respectively. It measured using.

At this time, when selecting the optimal process conditions of the hydrogen gas to silane gas ratio, the process time, process pressure, process power and process temperature were fixed at 10 seconds, 70 mTorr, 300 W and 100 ° C., respectively, and the optimum process conditions of the process pressure were set. When selected, the hydrogen gas to silane gas ratio, process time, process pressure and process temperature were fixed at 10, 10 seconds, 300 W and 100 ° C., respectively.

As shown in FIG. 5, it can be seen that the thickness gradually decreases as the amount of hydrogen gas increases, and at the same time, the surface roughness decreases and then increases again. This suggests that the proper addition of hydrogen gas plays an important role in the uniformity of the surface roughness and is effective in removing the structure of weak bonds by radical generation and etching generated on the surface.

Accordingly, the hydrogen gas to silane gas ratio is preferably formed with a thick thickness of the intrinsic layer 230, and the surface roughness is 8 to 10, which is a relatively low section.

In this case, when the hydrogen gas to silane gas ratio is 10, the thickness may also be thick, and the intrinsic layer 230 having excellent surface roughness may be formed.

As shown in Figure 6 it can be seen that when the process pressure proceeds to a process pressure of 0.1torr or less shows the best characteristics at 70 to 90mtorr.

It can be seen that the thickness of the intrinsic layer 230 is not only relatively thicker than other process pressures, but also the surface roughness is also lower than other process pressures.

At this time, it can be seen that the process pressure shows the most excellent characteristic at 90 mtorr.

Experimental Example 2

7 is a graph showing changes in thickness and bandgap of the intrinsic layer according to process power change.

8 is a graph showing Fourier transform infrared spectroscopy according to process power change.

Referring to FIGS. 7 and 8, the hydrogen gas to silane gas ratio, process time, process pressure, and process temperature of the process conditions are fixed at 10, 1200 seconds, 70 mTorr, and 300 ° C., respectively, and the process power is adjusted. As a result of changing the optimum process power, the intrinsic layer 230 having excellent characteristics at a process power of 200 to 300W was obtained.

As the process power increased, the thickness of the intrinsic layer 230 increased linearly, indicating that the number of radicals generated as the process power increased.

In order for the intrinsic layer 230 to be used as the intrinsic layer of the solar cell 200, the optical band gap is 1.6 to 1.8 eV, the dark conductivity is 109 to 1010 S / cm, and the photoconductivity is 104 to 105 S / cm. desirable.

Therefore, it can be seen that the graph shown in FIG. 7 shows the best results when the process power is 200 to 300W, preferably 300W.

At this time, as shown in the graph shown in Figure 8 for the process power of the 200 to 300W was observed at 2000cm-1 absorption peak in the Si-H stretching region with less defects. This suggests that even if the power is increased, the thin film is not destroyed by the high energy particles and the defects are bonded around the relatively small Si radicals, thereby showing the possibility of forming the high-quality intrinsic layer 230.

Experimental Example 3

9 is a graph showing the change of carrier life in the intrinsic layer with the process temperature.

Referring to FIG. 9, the hydrogen gas to silane gas ratio, the process time, the process pressure, and the process power of the process conditions are fixed at 10, 1200 seconds, 70 mTorr, and 300 W, respectively, and the process temperature is changed to optimally. As a result of examining the process temperature, the intrinsic layer 230 having excellent properties at a process temperature of 250 to 350 ° C. was obtained.

As shown in FIG. 9, it can be seen that as the process temperature increases, the carrier has a high carrier life at 250 to 350 ° C. and a carrier life of up to about 160 ns.

At this time, the lifetime of the carrier was measured and analyzed using a quasi-steady state photoconductivity decay (QSSPCD) method.

Therefore, in forming the intrinsic layer 230, it can be seen that the process temperature is preferably performed at 250 to 350 ° C.

Referring to FIG. 4 again, the solar cell manufacturing method of manufacturing the solar cell 200 will be described. A second type forming step (S440) of forming the second type layer after the intrinsic layer forming step (S430) will be described. Proceed.

The second type layer forming step (S440) is a step of forming the second type layer 240 on the intrinsic layer 230.

Like the intrinsic layer 230, the second type layer 240 may be formed of a chemical vapor deposition apparatus such as a plasma chemical vapor deposition apparatus.

In addition, the second type layer 240 may be formed using the inductively coupled plasma chemical vapor deposition apparatus 100.

In the present embodiment, a description will be given of a method of forming the second type layer 240 by the inductively coupled plasma chemical vapor deposition apparatus 100.

The second type layer forming step (S440) is a hydrogenated amorphous silicon layer doped with type 2 by adding diborene (B2H6) gas to the process conditions described above in the intrinsic layer forming step (S430), that is, type 2 a The second type layer 240 may be formed of a Si: H layer.

In addition, the second type layer forming step (S440) is a second type by using a mixed gas as a mixed gas containing hydrogen (H2) gas, silane (SiH4) gas, diborene (B2H6) gas and ethylene (C2H4) gas A doped hydrogenated amorphous carbide silicon layer, that is, a second type a-SiC: H layer may be formed.

Hereinafter, Experimental Example 4 and Experimental Example 5 of the mixed gas for forming the second type layer 230 made of the second type a-SiC: H layer using the inductively coupled plasma chemical vapor deposition apparatus 100 Experiments to select the optimal mixing conditions.

Experimental Example 4

FIG. 10 is a graph showing changes in deposition rate and optical bandgap of a hydrogenated amorphous silicon carbide thin film according to ethylene gas addition.

FIG. 11 is a graph showing a change in bonding structure of a hydrogenated amorphous silicon carbide thin film according to the addition of ethylene gas.

Referring to FIGS. 10 and 11, first, the hydrogen gas to silane gas ratio (H 2 / SiH 4) of the mixed gas including hydrogen gas and hydrogen gas to include ethylene gas is fixed to 6, and the process power is 600 W and the process. The temperature was fixed at 250 ° C.

And ethylene gas diluted with 60% hydrogen gas was increased from 0sccm to 8sccm and mixed in the mixed gas. At this time, the total flow rate of the mixed gas containing the ethylene gas was fixed at 100 sccm.

Deposition rate and optical band gap were measured using Stylus profiler and Scanning Probe Microscope, respectively.

It can be seen that as the mixing ratio of ethylene gas is increased, the deposition rate gradually decreases, and at the same time, the optical bandgap increases to 2.9 eV. This is a role of hydrogen contained in ethylene gas, which shows low deposition rate by etching weak bonding groups on the surface of the thin film and eliminates defects in the band gap as carbon and hydrogen are doped in amorphous silicon. It can be seen that the expansion, the peak of Si-C (790cm-1) and CH (2800 ~ 3000cm-1) was observed when the ethylene gas was increased, but gradually increases as it is moved.

In addition, the peak of Si-H2 (2090cm-1) with many defects was observed, and the intensity of the peak gradually increased. In general, the ethylene gas ratio (the amount of ethylene gas / the amount of gas introduced) is about 10-2, and the ethylene gas is preferably mixed at a ratio of 1 to 1.2% with respect to the total mixed gas.

Experimental Example 5

FIG. 12 is a graph showing changes in optical bandgap and safety of a hydrogenated amorphous silicon carbide layer doped with type 2 with the addition of diborene gas.

FIG. 13 is a graph showing a change in characteristics of a solar cell according to the thickness of a hydrogenated amorphous silicon carbide layer doped with a second type.

Referring to FIGS. 12 and 13, in the process conditions of Experimental Example 5, the ethylene gas was fixed at 1.2 sccm, the other process conditions were the same, and the diborene gas was increased from 0 sccm to 8 sccm, thereby mixing gas. Mixed in.

At this time, the diborene gas is diborene gas diluted with 97% hydrogen gas.

The optical bandgap and electrical conductivity of the hydrogenated amorphous silicon carbide layer doped with a mold by varying the flow rate of the diborene gas were analyzed.

As the diborene gas increases, the bandgap decreases from 2.2eV to 1.98eV, indicating that defects are caused by boron atoms doped in the extended bandgap.

In addition, the dark electrical conductivity can be seen that increases to 5 × 10 -6 S / cm. When the diborene gas is mixed at about 6 sccm, that is, the diborene gas ratio (diborene gas amount / total amount of gas introduced) shows the best characteristics at 6 to 6.5%.

In addition, when the thickness of the solar cell is applied to the second layer type 240 using the process conditions and the thickness is changed from 9 to 15 nm, the open voltage, the current density, the fidelity, and the conversion efficiency are compared, and the open voltage is high at about 12 nm. (0.81V), current density (21.1mA / cm2), fidelity (0.53) and conversion efficiency of 9.08%.

Referring to FIG. 4, the solar cell manufacturing method for manufacturing the solar cell 200 is continuously described. After the second type layer forming step S440 is performed, the second electrode forming step S450 is performed. Proceed.

In the second electrode forming step S450, the transparent electrode layer 252 is formed on the second type layer 240, and the patterned metal electrode 254 is formed on the transparent electrode layer 252.

The transparent electrode layer 252 may be formed by depositing a transparent conductive oxide such as TCO, for example, ZnO, AZO, ITO, SnO 2: F, or the like by using a physical vapor deposition apparatus or a chemical vapor deposition apparatus.

In addition, the metal electrode 254 is formed of a conductive material, such as aluminum, by a physical vapor deposition apparatus, and then patterned to form a patterned metal electrode 254 or a patterned metal by a physical vapor deposition apparatus using a pattern mask. The method of forming the electrode 254 can be used.

14 is a flowchart illustrating a process sequence of a solar cell manufacturing method according to another embodiment of the present invention.

Referring to FIG. 14, in the solar cell manufacturing method according to another exemplary embodiment, a transparent substrate preparation step (S510), a first electrode forming step (S520), a second type layer forming step (S530), and a buffer are formed. A step S540, an intrinsic layer forming step S550, a first type layer forming step S560, a transparent electrode layer forming step S570, and a second electrode forming step S580 are included.

At this time, the solar cell manufacturing method according to another embodiment of the present invention will be described a solar cell manufacturing method based on the solar cell 300 described with reference to FIG.

The transparent substrate preparation step 510 is a step of preparing a transparent substrate 310 which is a transparent and insulator such as a glass substrate or a plastic substrate.

The preparing of the transparent substrate 510 may include removing organic materials from the transparent substrate 310. That is, the transparent substrate preparation step 510 includes a process of removing organic materials, etc. using the trichloro ethylene (TCE), acetone, and methanol from the transparent substrate 310.

In addition, the preparing of the transparent substrate 510 may include a drying process of drying the transparent substrate 310. That is, a drying process for removing moisture adsorbed to the transparent substrate 310 is performed in the process of removing organic matters from the transparent substrate 310. The drying process may be a process of charging the transparent substrate 310 to a vacuum chamber or the like and heating the substrate 200 at 200 ° C. for 2 hours in a state where oxygen is removed.

The first electrode forming step (S520) is a step of forming a first electrode 310 made of a TCO layer on the transparent substrate 310.

The TCO layer may be formed by depositing a transparent conductive oxide such as ZnO, AZO, ITO and SnO 2: F with a physical vapor deposition apparatus or a chemical vapor deposition apparatus.

At this time, the first electrode 310 performs a texture process by performing a wet process with diluted hydrochloric acid.

The first electrode 310 is provided with a plurality of projections, preferably pyramidal formation projections on the surface by the inter-texture process.

The second type layer forming step 530 is a step of forming the second type layer 330 on the first electrode 310, the same method as the second type forming step S440 described with reference to FIG. 4. Detailed description is omitted since it can be formed as.

The buffer layer forming step (S540) is a process that is performed in succession with the second type layer forming step 530 so that the buffer layer 340 is doped to a concentration lower than the concentration of the second type impurity forming the second type layer 330. Forming a step.

Therefore, the buffer layer forming step (S540) is a step of forming the buffer layer 340 under process conditions in which the amount of the second type gas, for example, diborene (B2H6) gas is reduced in the second type layer forming step 530. Description is omitted.

The intrinsic layer forming step S550 may be formed in the same manner as the intrinsic layer forming step S450 described with reference to FIG. 4.

The intrinsic layer forming step (S550) is a step of forming a hydrogenated fine crystalline silicon layer, that is, an I μc-Si: H layer, which is not doped with impurities.

Experimental Example 6 is to form the intrinsic layer 350 as a hydrogenated microcrystalline silicon layer, that is, an I μc-Si: H layer, which is not doped with impurities using the inductively coupled plasma chemical vapor deposition apparatus 100. It is an experiment for selecting the optimum condition of the mixed gas and the process pressure.

Experimental Example 6

15 is a graph showing the change in the electrical conductivity and activation energy of the hydrogenated microcrystalline silicon layer of the intrinsic layer according to the amount of silane gas.

16 is a graph showing the change of the crystallization peak and the amorphous peak according to the amount of silane gas.

17 is a graph showing a change in electrical characteristics of the hydrogenated microcrystalline silicon layer of the intrinsic layer with the change of the process power.

Referring to FIGS. 15 to 17, the mixed gas of silane gas and hydrogen gas increases the silane gas ratio (SiH 4 / (SiH 4 + H 2)) from 0.016 to 0.045, and increases the process power from 800 to 1400 W. Changed.

As shown in FIGS. 15 and 16, the dark, photoconductivity and activation energy of the intrinsic layer according to the silane gas ratio were measured. At this time, the process power is 1200W, the process pressure is 70mtorr and the process temperature is 250 ℃.

In this case, it can be seen that the silane gas ratio is 0.016 to 0.02 under the condition that the photoconductivity is the highest and satisfies the activation energy range. That is, as the silane gas ratio decreases, that is, as the flow rate of the silane gas increases, the intensity of the crystal peak of 520 cm −1 decreases, and at the same time, the peak of 480 cm −1 increases.

In this case, when the silane gas ratio is 0.02, it shows a crystallinity of about 68% or more.

As shown in FIG. 17, the process power was a condition that satisfies the activation energy range while having the highest photoconductivity at 1150 to 1250W.

In this case, the second type layer 330 and the first type layer 360 may also be formed of a hydrogenated fine crystalline silicon layer.

Hereinafter, Experimental Example 7 is hydrogenated microcrystalline crystalline doped with the type 2 and type 1 impurities of the second type layer 330 and the first type layer 360 using the inductively coupled plasma chemical vapor deposition apparatus 100. It is an experiment for selecting the optimum mixing conditions of the mixed gas for forming into the silicon layer, that is, the second type and the first type μc-Si: H layer.

Experimental Example 7

18 is a graph showing the change of the optical band gap and the dark conductance according to the phosphine gas ratio.

19 is a graph showing the change of the optical band gap and the dark conductance according to the diborene gas ratio.

Referring to FIGS. 18 and 19, the method for miniaturizing and crystallizing the second type layer 330 and the first type layer 360 may be based on the force of the silane gas in the mixed gas while maintaining the process conditions in Experimental Example 6. The ratio of fin gas and diborene gas was varied to select the optimal phosphine gas ratio and diborene gas ratio.

The second type layer 330 uses a mixed gas containing 0.075 to 0.1% of a phosphine gas for the silane gas, and the first type layer 360 has a diborene gas of 0.1 to 0.5 for the silane gas. Preference is given to using mixed gas contained in%.

As shown in FIGS. 18 and 19, when the phosphine gas ratio increases, both the band gap and the dark conductivity value decrease, and as the diborene gas ratio increases, the band gap decreases and the dark conductivity value increases. It is understood from what there is.

Referring to FIG. 14, the solar cell manufacturing method for manufacturing the solar cell 300 will be described in detail. After proceeding with the intrinsic layer forming step S550, the second type layer forming step S560 is performed. do.

In the first type layer forming step S560, only the impurities are changed to the first type in the second type forming layer step S440 described with reference to FIG. 4, and the first type hydrogenation amorphous silicon layer may be formed in a similar manner. Since the first type of impurities as described above in Experimental Example 7 may be formed of the hydrogenated fine crystalline silicon layer doped, detailed description thereof will be omitted.

The transparent electrode layer forming step (S570) is performed by depositing a transparent conductive oxide such as a TCO layer, that is, ZnO, AZO, ITO and SnO 2: F, on the first type layer 360 by a physical vapor deposition apparatus or a chemical vapor deposition apparatus. Since the step of forming the TCO layer as described above has been described above, a detailed description thereof will be omitted.

The second electrode forming step S580 is a step of forming a conductive material such as aluminum on the transparent electrode layer 370 as a physical vapor deposition apparatus.

Since the second electrode forming step S580 may be formed by a method of forming a general conductive electrode, a detailed description thereof will be omitted.

The present invention has been described above with reference to the above embodiments, but the present invention is not limited thereto. It will be apparent to those skilled in the art that modifications and variations may be made without departing from the spirit and scope of the invention, and that such modifications and variations are also contemplated by the present invention.

1 is a conceptual diagram illustrating a schematic configuration of an inductively coupled plasma chemical vapor deposition apparatus used in a solar cell manufacturing method according to embodiments of the present invention.

2 is a cross-sectional view showing an embodiment of a solar cell manufactured by a solar cell manufacturing method according to an embodiment of the present invention.

3 is a cross-sectional view showing another embodiment of a solar cell manufactured by a solar cell manufacturing method according to another embodiment of the present invention.

4 is a flowchart illustrating a process sequence of a solar cell manufacturing method according to an embodiment of the present invention.

5 is a graph showing changes in thickness and surface roughness of an intrinsic layer according to a hydrogen gas to silane gas ratio of a mixed gas.

6 is a graph showing the thickness and surface roughness of the intrinsic layer with the change of the process pressure.

7 is a graph showing changes in thickness and bandgap of the intrinsic layer according to process power change.

8 is a graph showing Fourier transform infrared spectroscopy according to process power change.

9 is a graph showing the change of carrier life in the intrinsic layer with process temperature.

FIG. 10 is a graph showing changes in deposition rate and optical bandgap of a hydrogenated amorphous silicon carbide thin film according to ethylene gas addition.

11 is a graph showing the change in bonding structure of the hydrogenated amorphous silicon carbide thin film with the addition of ethylene gas.

FIG. 12 is a graph showing changes in optical bandgap and safety of a hydrogenated amorphous silicon carbide layer doped with type 2 with the addition of diborene gas.

FIG. 13 is a graph showing a change in characteristics of a solar cell according to the thickness of a hydrogenated amorphous silicon carbide layer doped with a second type.

14 is a flowchart illustrating a process sequence of a solar cell manufacturing method according to another embodiment of the present invention.

15 is a graph showing the change in the electrical conductivity and activation energy of the hydrogenated microcrystalline silicon layer of the intrinsic layer according to the amount of silane gas.

16 is a graph showing the change of the crystallization peak and the amorphous peak according to the amount of silane gas.

17 is a graph showing a change in electrical characteristics of the hydrogenated microcrystalline silicon layer of the intrinsic layer with the change of the process power.

18 is a graph showing the change of the optical band gap and the dark conductance according to the phosphine gas ratio.

19 is a graph showing the change of the optical band gap and the dark conductance according to the diborene gas ratio.

<Explanation of symbols for the main parts of the drawings>

210: first electrode 220: first type layer

230: intrinsic layer 240: type 2 layer

250: second electrode

Claims (22)

In manufacturing a solar cell including a first electrode, a first type layer, an intrinsic layer, a second type layer and a second electrode, Including an intrinsic layer forming step of forming the intrinsic layer consisting of a hydrogenated amorphous silicon thin film using an inductively coupled plasma chemical vapor deposition apparatus using a mixed gas containing hydrogen (H2) gas and silane (SiH4) gas, And the mixed gas has a hydrogen gas to silane gas ratio (H2 / SiH4 ratio) of 8 to 10 of the hydrogen gas and silane gas. The method of claim 1, The intrinsic layer forming step is a solar cell manufacturing method, characterized in that the process pressure is 70 to 90mtorr, the process power is 200 to 300W, the process temperature is 250 to 350 degrees. The method of claim 1, The solar cell manufacturing method: silver Before the intrinsic layer forming step, A first type silicon substrate preparing step of preparing a first type silicon substrate; And A first electrode forming step of forming the first electrode on a rear surface of the first type silicon substrate; After the intrinsic layer forming step, A second type forming step of forming a second type layer on the intrinsic layer; And And a second electrode forming step of forming a second electrode on the second type layer. The method of claim 3, wherein The first electrode is made of Ag, The second type layer is made of a hydrogenated second type amorphous silicon layer, And the second electrode comprises a transparent electrode layer formed on the second type layer and a patterned aluminum electrode formed on the transparent cathode layer. The method of claim 1, The solar cell manufacturing method: silver Before the intrinsic layer forming step, A transparent substrate preparation step of preparing a transparent substrate; A first electrode forming step of forming the first electrode on the transparent substrate; And And a second type layer forming step of forming the second type layer on the first electrode. After the intrinsic layer forming step, A first type layer forming step of forming the first type layer on the intrinsic layer; And And a second electrode forming step of forming the second electrode on the first type layer. The method of claim 5, Between the second type layer forming step and the intrinsic layer forming step, A buffer layer forming step of forming a buffer layer, Between the first type layer forming step and the second electrode forming step, And a transparent electrode layer forming step of forming a transparent electrode layer on the first type layer. The method of claim 1, The first electrode is made of a TCO layer, the second electrode is a solar cell manufacturing method, characterized in that made of aluminum. In manufacturing a solar cell including a first electrode, a first type layer, an intrinsic layer, a second type layer and a second electrode, The amorphous silicon carbide thin film is formed using an inductively coupled plasma chemical vapor deposition apparatus using a mixed gas including hydrogen (H 2) gas, silane (SiH 4) gas, diborene (B 2 H 6) gas, and ethylene (C 2 H 4) gas. A second type layer forming step of forming a type 2 layer, The ethylene gas is ethylene gas 60% diluted with hydrogen gas, the diborene gas is diborene gas 97% diluted with hydrogen gas, The ethylene gas is contained in 1 to 1.2% in the mixed gas, the diborene gas is a solar cell manufacturing method, characterized in that contained in 6 to 6.5% in the mixed gas. The method of claim 8, The solar cell manufacturing method: silver Before the second type layer forming step, A first type silicon substrate preparing step of preparing a first type silicon substrate; A first electrode forming step of forming the first electrode on a rear surface of the first type silicon substrate; And And an intrinsic layer forming step of forming the intrinsic layer on the entire surface of the first type silicon substrate. After the second type layer forming step, And a second electrode forming step of forming a second electrode on the second type layer. The method of claim 8, The first electrode is made of Ag, The intrinsic layer is composed of a hydrogenated amorphous silicon layer, And the second electrode comprises a transparent electrode layer formed on the second type layer and a patterned aluminum electrode formed on the transparent electrode layer. The method of claim 8, The solar cell manufacturing method: silver Before the second type layer forming step, A transparent substrate preparation step of preparing a transparent substrate; And A first electrode forming step of forming the first electrode on the transparent substrate; After the second type layer forming step, An intrinsic layer forming step of forming the intrinsic layer on the second type layer; A first type layer forming step of forming the first type layer on the intrinsic layer; And And a second electrode forming step of forming the second electrode on the first type layer. The method of claim 11, Between the second type layer forming step and the intrinsic layer forming step, A buffer layer forming step of forming a buffer layer, Between the first type layer forming step and the second electrode forming step, And a transparent electrode layer forming step of forming a transparent electrode layer on the first type layer. The method of claim 11, The first electrode is made of a TCO layer, the second electrode is a solar cell manufacturing method, characterized in that made of aluminum. In manufacturing a solar cell including a first electrode, a first type layer, an intrinsic layer, a second type layer and a second electrode, Silicon layer crystallized from any one of the type 2 layer, intrinsic layer and type 1 layer using an inductively coupled plasma chemical vapor deposition apparatus using a mixed gas containing hydrogen (H 2) gas and silane (SiH 4) gas Formed to consist of, The mixed gas has a silane gas ratio (SiH 4 / (SiH 4 + H 2)) of 0.016 to 0.02. The method of claim 14, The inductively coupled plasma chemical vapor deposition apparatus is a solar cell manufacturing method characterized in that using a process power of 1150 to 1250W. The method of claim 14, Forming the first type layer into a crystallized silicon layer may use a mixed gas containing phosphine (P2H3) gas, but using a mixed gas containing 0.075 to 0.1% of phosphine gas to the silane gas. A solar cell manufacturing method characterized by the above-mentioned. The method of claim 14, Forming the second type layer from the crystallized silicon layer may use a mixed gas containing diborene gas, but using a mixed gas containing 0.1 to 0.5% of diborene gas to the silane gas. Solar cell manufacturing method. The method of claim 14, The solar cell manufacturing method: silver A first type silicon substrate preparing step of preparing a first type silicon substrate; A first electrode forming step of forming the first electrode on a rear surface of the first type silicon substrate; And An intrinsic layer forming step of forming the intrinsic layer on the entire surface of the first type silicon substrate; A second type layer forming step of forming the second type layer on the intrinsic layer; And And a second electrode forming step of forming a second electrode on the second type layer. The method of claim 18, The first electrode is made of Ag, And the second electrode comprises a transparent electrode layer formed on the second type layer and a patterned aluminum electrode formed on the transparent electrode layer. The method of claim 14, The solar cell manufacturing method: silver A transparent substrate preparation step of preparing a transparent substrate; A first electrode forming step of forming the first electrode on the transparent substrate; A second type layer forming step of forming the second type layer on the first electrode; An intrinsic layer forming step of forming the intrinsic layer on the second type layer; A first type layer forming step of forming the first type layer on the intrinsic layer; And And a second electrode forming step of forming the second electrode on the first type layer. The method of claim 20, Between the second type layer forming step and the intrinsic layer forming step, A buffer layer forming step of forming a buffer layer, Between the first type layer forming step and the second electrode forming step, And a transparent electrode layer forming step of forming a transparent electrode layer on the first type layer. The method of claim 21, The first electrode is made of a TCO layer, the second electrode is a solar cell manufacturing method, characterized in that made of aluminum.

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