TWI524545B - Method of Making Solar Cell Structure - Google Patents

Description

Solar cell structure manufacturing method

The present invention relates to a solar cell, and more particularly to a method of fabricating a wafer solar cell.

The constituent atoms of the single crystal germanium are periodically arranged according to a certain rule. The method is prepared by melting a base metal (purity of 99.999999999%, 11 9) into a quartz crucible, and then inserting the seed crystal into the liquid surface to Rotate at a rate of 2 to 20 revolutions per minute, and slowly pull up at a speed of 0.3 to 10 mm per minute. Thus, a single crystal of 4 to 8 inches in diameter can be formed. This method is called Chai's length. The Czochralski method, a solar cell made of single crystal germanium, has high efficiency and stable performance and has been widely used.

In recent years, international oil prices have been rising and nuclear safety is worrying. While Taiwan's energy relies on imported coal and nuclear power, thermal power and nuclear power account for the vast majority of Taiwan's power generation. In order to reduce dependence on imports and to make Taiwan's nuclear facilities too old and life threatening, Renewable energy needs to receive considerable attention for the land of Taiwan.

Among the many renewable energy sources, solar cells are most suitable for universal development. Because Taiwan is located in the subtropical zone, it has a strong sunshine in the past year, and Taiwan has great advantages in solar cell manufacturing, such as the maturity of the semiconductor industry and the global sun. Battery shipments occupy a leading role, so it has the advantage of developing semiconductor solar cells.

In the current solar cell fabrication process, the surface of the substrate is first cleaned by an RCA cleaning process, and then the surface of the substrate is structured, and the structured surface is cleaned using an acidic solution, and then a P-type semiconductor layer or an N-type semiconductor layer is formed using a diffusion process. On the surface of the substrate, while diffusing the P-type half The conductor layer or the N-type semiconductor layer is dependent on the type of the substrate. Currently, the P-type semiconductor doped germanium is used as the substrate, and the N-type semiconductor doping layer is diffused at a high temperature, and then the edge of the diffused substrate is etched by etching. The substrate surface oxide is also removed by etching, and then an anti-reflection layer is formed on the surface of the substrate, and finally a metal electrode is fabricated.

From the above production process, it can be known that the production of solar cells needs to be combined through a number of different processes. Therefore, how to increase the efficiency value of solar cells and simplify the cost invested in the process is a very important issue, and anti-reflection technology is the most important, such as etching the surface with an acidic solution or preparing an anti-reflection layer on the surface. Widely used, however, the surface is etched with an acidic solution or an anti-reflective layer is prepared on the surface, which requires multiple processes and increases manufacturing costs. After the anti-reflection layer is fabricated, a metal electrode is fabricated to produce a metal electrode. In this case, the effect of the anti-reflection film is degraded, thereby reducing the anti-reflection effect, thereby reducing the amount of light entering and reducing the efficiency of the solar cell.

In view of this, in order to improve the efficiency of the solar cell of the wafer, the present invention provides a high-performance protective effect of the high dielectric material cerium oxide (HfO2) as a passivation layer, and at the same time, after the metal electrode is fabricated, the anti-reflection is prepared by using the microsphere structure. Layer to avoid performance degradation of the anti-reflective layer.

The structure of the invention comprises a P-type metal contact electrode, a P-type semiconductor layer, a single crystal P-type substrate, an N-type semiconductor layer, an N-type metal contact electrode, a surface passivation layer and a microspherical structured anti-reflection a layer, wherein the N-type semiconductor layer and the P-type semiconductor layer are respectively located on an upper side and a lower side of the single crystal P-type substrate, and the P-type metal contact electrode is located on a lower side of the P-type semiconductor layer, and the surface passivation layer is located at the bottom side On the upper side of the N-type semiconductor layer, the N-type metal contact electrode has a specific pattern distribution and is connected to the N-type semiconductor layer through the surface passivation layer, and the micro-spherical structured anti-reflection layer is located without the N-type metal contact electrode The surface passivation layer is on the upper side.

In the present invention, the surface passivation layer is first formed on the upper side of the N-type semiconductor layer, and the N-type metal contact electrode is distributed on the upper side of the surface passivation layer, and after the baking, the N-type metal contact is performed. The electrode is connected to the N-type semiconductor layer through the surface passivation layer, and finally the microspherical structured anti-reflection layer is formed on the upper side of the surface passivation layer not having the N-type metal contact electrode.

Accordingly, the surface passivation layer can provide an efficient protection effect, and the microspherical structured anti-reflection layer can be arranged to avoid reflection of sunlight, increase the throughput of sunlight, and the micro-spherical structured anti-reflection The layer is finally formed, so that the performance degradation of the microspherical structured anti-reflective layer can be avoided, thereby improving the efficiency of the solar cell.

10‧‧‧P type metal contact electrode

20‧‧‧P type semiconductor layer

30‧‧‧Single crystal P-type substrate

40‧‧‧N type semiconductor layer

50‧‧‧N type metal contact electrode

60‧‧‧ surface passivation layer

70‧‧‧Microspherical structured anti-reflective layer

1 is a schematic structural view of a preferred embodiment of the present invention.

2A is a schematic structural view of the semi-finished product of the present invention.

2B is a schematic structural view 2 of the semi-finished product of the present invention.

The detailed description of the present invention and the technical description of the present invention are further illustrated by the accompanying drawings, but it should be understood that these embodiments are merely illustrative and not to be construed as limiting.

Referring to FIG. 1 , the structure of the present invention includes a P-type metal contact electrode 10 , a P-type semiconductor layer 20 , a single crystal P-type substrate 30 , an N-type semiconductor layer 40 , and an N-type metal contact electrode 50 . a surface passivation layer 60 and a microspherical structured anti-reflective layer 70, wherein the N-type semiconductor layer 40 and the P-type semiconductor layer 20 are respectively located on the upper side and the lower side of the single crystal P-type substrate 30, the P-type The metal contact electrode 10 is located on the lower side of the P-type semiconductor layer 20, and the surface passivation layer 60 is located on the upper side of the N-type semiconductor layer 40. The N-type metal contact electrode 50 has a specific pattern distribution and passes through the table. The surface passivation layer 60 is connected to the N-type semiconductor layer 40, and the micro-spherical structured anti-reflection layer 70 is located on the upper side of the surface passivation layer 60 having the N-type metal contact electrode 50.

The surface of the single crystal P-type substrate 30 that is in contact with the N-type semiconductor layer 40 may be a sawtooth surface that allows the N-type semiconductor layer 40, the surface passivation layer 60, and the microspherical structured anti-reflective layer 70. They all have a serrated surface, which can increase the anti-reflection effect and increase the battery efficiency of the solar cell structure.

In the manufacturing method of the present invention, first, a single crystal P-type substrate 30 is taken, and the single crystal P-type substrate 30 is washed with acetone for 10 minutes, ethanol washed for 10 minutes, and deionized water (DI Water) for 10 minutes, and then Dry at 100 degrees Celsius for 10 minutes.

The N-type semiconductor layer 40 is formed on the single crystal P-type substrate 30, and the phosphorus diffusion solution is uniformly spin-coated onto the single crystal P-type substrate 30 using a spin coater to allow the single crystal P-type substrate. 30 is coated with phosphorus, and its rotation speed is set to two stages, the first rotation speed is 1000 rpm, the time is 15 seconds, the second rotation speed is 3000 rpm, and the time is 20 seconds. The single crystal P-type substrate 30 was placed in a high-temperature furnace tube through which nitrogen gas was passed, and baked at 200 ° C for 15 minutes to dry the surface diffusion source organic matter. Then, the single crystal P-type substrate 30 is placed in a rapid annealing furnace, which is first evacuated, and vacuum is drawn to 100 mTorr and then nitrogen gas is introduced, and the nitrogen gas is maintained at 4-6 Torr (torr The annealing temperature is 950 degrees Celsius for about 60 seconds, that is, the fabrication of the N-type semiconductor layer 40 is completed.

Before the N-type semiconductor layer 40 is formed on the single crystal P-type substrate 30, the single crystal P-type substrate 30 contacts the surface of the N-type semiconductor layer 40, and the sawtooth surface can be formed by an etching process. The N-type semiconductor layer 40, the surface passivation layer 60, and the microspherical structured anti-reflective layer 70 each have a serrated surface.

The P-type semiconductor layer 20 is formed under the single crystal P-type substrate 30, and the boron diffusion solution is uniformly spin-coated onto the single crystal P-type substrate 30 using a spin coater to allow the single crystal P-type substrate. 30 is coated with boron, and its rotation speed is set to two stages, and the first rotation speed is 2000 rpm, the time is 10 seconds, the second rotation speed is 3000 rpm, and the time is 20 seconds. The single crystal P-type substrate 30 was placed in a high-temperature furnace tube through which nitrogen gas was passed, and baked at 200 ° C for 15 minutes to dry the surface diffusion source organic matter. Then, the single crystal P-type substrate 30 is placed in a rapid annealing furnace, and then vacuumed first, and vacuum is drawn to 100 mTorr or less, and nitrogen gas is supplied thereto, and the nitrogen gas is maintained at 4-6 Torr (torr The annealing temperature is 950 degrees Celsius for about 60 seconds, that is, the fabrication of the P-type semiconductor layer 20 is completed.

The surface passivation layer 60 is formed by depositing a hafnium oxide (HfO 2 ) film using a sputtering system, controlling the radio frequency (rf) power to 100-300 watts (W), and introducing 95% argon (Ar). Gas and 5% oxygen for 4 minutes, chamber pressure controlled at 5 mTorr, and thickness of approximately 80 nm (nm).

Please refer to FIG. 2A and FIG. 2B together. The N-type metal contact electrode 50 is formed by vapor deposition of aluminum on the surface passivation layer 60 by a thermal vapor deposition system (eg, FIG. 2A). And a thickness of about 150 nanometers (nm), and after the formation of the N-type metal contact electrode 50, a baking process is performed, and the N-type metal contact electrode 50 is allowed to penetrate the surface by the baking process. The passivation layer 60 enters the N-type semiconductor layer 40 (as shown in FIG. 2B).

Similarly, the P-type metal contact electrode 10 is formed by vapor-depositing aluminum under the P-type semiconductor layer 20 in a thermal vapor deposition system to a thickness of about 300 nanometers (nm).

Finally, the microspherical structured anti-reflective layer 70 is formed by uniformly coating the material of the microspherical structured anti-reflective layer 70 and the ceria (SiO2) particle powder solution using a spin coater. The surface passivation layer 60 has one side of the N-type metal contact electrode 50. This stage controls the first rotation at 1000 rpm, the spin coating time is 10 seconds, the second rotation is controlled at 1000-5000 rpm, and the spin coating time is 20-40 seconds. The spin-coated structure was placed in a high-temperature annealing furnace and treated at 300 ° C for 10 minutes for the purpose of crystallizing the interior of the cerium oxide (SiO 2 ) particles.

As described above, the present invention forms a surface passivation layer and a microspherical structured anti-reflective layer within the structure of the solar cell, through which the protective layer can provide a protective effect, and the microspherical structured anti-reflective layer is disposed, The throughput of the sunlight can be increased, and the microspherical structured anti-reflection layer is fabricated after the P-type metal contact electrode and the N-type metal contact electrode are formed, thereby maintaining a good anti-reflection effect, thereby improving the solar cell. effectiveness.

10‧‧‧P type metal contact electrode

20‧‧‧P type semiconductor layer

30‧‧‧Single crystal P-type substrate

40‧‧‧N type semiconductor layer

50‧‧‧N type metal contact electrode

60‧‧‧ surface passivation layer

70‧‧‧Microspherical structured anti-reflective layer

Claims (6)

The method for fabricating a solar cell structure according to claim 1, wherein the surface passivation layer is first formed on the upper side of the N-type semiconductor layer, and the N-type metal contact electrode is distributed on the surface in a specific pattern. After the upper side of the passivation layer is baked, the N-type metal contact electrode is connected to the N-type semiconductor layer through the surface passivation layer, and finally the micro-layer is formed on the upper surface of the surface passivation layer without the N-type metal contact electrode. a spherical structured antireflection layer, wherein the N-type semiconductor layer is formed on the single crystal P-type substrate, wherein a spin coating machine is used to uniformly spin-coat a phosphorus diffusion solution onto the single crystal P-type substrate, and the rotation speed thereof Set to two stages, the first rotation speed is 1000 rpm, the time is 15 seconds, the second rotation speed is 3000 rpm, and the time is 20 seconds. Then, the single crystal P type substrate is placed in a high temperature furnace tube of nitrogen gas. And baking at 200 degrees Celsius, baking time is 15 minutes to dry the surface diffusion source organic matter, and then placing the single crystal P-type substrate in a rapid annealing furnace, first evacuating it, and vacuuming to 100 millimeters Below the ear, nitrogen is introduced. The nitrogen gas is maintained at 4-6 Torr, and the annealing temperature is 950 ° C for about 60 seconds to complete the fabrication of the N-type semiconductor layer. The method for fabricating a solar cell structure according to claim 1, wherein the single crystal P-type substrate contacts the surface of the N-type semiconductor layer before forming the N-type semiconductor layer on the single crystal P-type substrate, A sawtooth surface is formed by the etching process. The method for fabricating a solar cell structure according to claim 1, wherein the P-type semiconductor layer is formed under the single crystal P-type substrate, and the boron diffusion solution is uniformly spin-coated by using a spin coater. The rotation speed of the single crystal P-type substrate is set to two stages, the first rotation speed is 2000 rpm, the time is 10 seconds, the second rotation speed is 3000 rpm, and the time is 20 seconds. Into a high temperature furnace tube of nitrogen, and baked at 200 degrees Celsius, baking time is 15 minutes to dry the surface diffusion source organic matter, and then the single crystal P-type substrate is placed in a rapid annealing furnace, first pumping it Vacuum, vacuum pumped to 100m Below the ear, nitrogen gas was introduced, the nitrogen gas was maintained at 4-6 Torr, and the annealing temperature was 950 degrees Celsius for about 60 seconds to complete the fabrication of the P-type semiconductor layer 20. The method for fabricating a solar cell structure according to claim 1, wherein the surface passivation layer is formed by depositing a ruthenium dioxide film using a sputtering system, and the RF power is controlled at 100-300 watts. 95% argon and 5% oxygen were added for 4 minutes, the chamber pressure was controlled at 5 mTorr, and the thickness was about 80 nm. The method for fabricating a solar cell structure according to claim 1, wherein the N-type metal contact electrode is formed by vapor-depositing aluminum on the surface passivation layer by a thermal vapor deposition system, and has a thickness of about 150. After the N-type metal contact electrode is formed, the N-type metal contact electrode is infiltrated into the surface passivation layer to be connected to the N-type semiconductor layer by a baking process. The method for fabricating a solar cell structure according to claim 1, wherein the microspherical structured antireflection layer is formed by using a spin coater to form the microspherical structured antireflection layer. The cerium oxide particle powder solution is uniformly coated on the side of the surface passivation layer having the N-type metal contact electrode. At this stage, the first rotation is controlled at 1000 rpm, the spin coating time is 10 seconds, and the second rotation is controlled at 1000-5000 rpm. The spin coating time is 20-40 seconds, and the spin-coated structure is placed in a high-temperature annealing furnace for treatment at 300 ° C for 10 minutes for the purpose of crystallizing the interior of the cerium oxide particles.