Photovoltaic solar cell and method of manufacturing photovoltaic solar cell
Provided is a method of manufacturing a photovoltaic solar cell, including: forming a first conductivity type region that contains a first conductivity dopant, on one surface of a semiconductor substrate and an opposite surface that is opposite to the one surface; removing the first conductivity type region formed on the opposite surface of the semiconductor substrate by performing dry etching; and forming a second conductivity type region that contains a second conductivity type dopant, on the opposite surface of the semiconductor substrate.
1. A method of manufacturing a photovoltaic solar cell, the method comprising:
forming a polycrystalline layer, which is a first conductivity type region that contains a first conductivity dopant, on one surface of a single crystalline semiconductor substrate and an opposite surface that is opposite to the one surface simultaneously by performing a Low-Pressure Chemical Vapor Deposition (LPCVD);
performing a first dry etching to remove the polycrystalline layer, which is the first conductivity type region, doped with the first conductivity dopant and formed on the opposite surface of the single crystalline semiconductor substrate, remaining the polycrystalline which is the first conductivity type region, doped with the first conductivity dopant and formed on the one surface of the single crystalline semiconductor substrate, and to remove an edge portion of the polycrystalline layer, which is the first conductivity type region, doped with the first conductivity dopant and formed on the one surface of the single crystalline semiconductor substrate to provide an isolation, and performing a second dry etching continuously to form a minute V-shaped protrusion on the opposite surface of the single crystalline semiconductor substrate; and
forming a second conductivity type region that contains a second conductivity dopant on the opposite surface of the single crystalline semiconductor substrate by diffusing the second conductivity dopant into the single crystalline semiconductor substrate,
wherein the first dry etching is performed by reactive ion etching (RIE) using sulfur hexafluoride gas and oxygen gas,
wherein a volume ratio of the sulfur hexafluoride gas to the oxygen gas is 3 to 5, and
wherein the minute V-shaped protrusion is further formed on an inclined portion of the first conductivity type region on the one surface of the single crystalline semiconductor substrate, the inclined portion being a part that remained after the edge portion of the first conductivity type region that was removed by the first dry etching.
2. The method of manufacturing a photovoltaic solar cell according to claim 1 , wherein an amount of the sulfur hexafluoride gas is used at a flow rate of 8000 sccm to 10000 sccm.
3. The method of manufacturing a photovoltaic solar cell according to claim 1 , wherein a plasma power for the reactive ion etching is 25 kw to 30 kw.
4. The method of manufacturing a photovoltaic solar cell according to claim 1 , wherein a pressure for the second dry etching to form the minute V-shaped protrusion is equal to or higher than that for the first dry etching to remove the first conductivity type region.
5. The method of manufacturing a photovoltaic solar cell according to claim 1 , wherein the first dry etching of the first conductivity type region and the second dry etching to form the minute V-shaped protrusion are performed by an in-situ process.
6. The method of manufacturing a photovoltaic solar cell according to claim 1 , further comprising;
forming a control passivation layer on the one surface of the single crystalline semiconductor substrate before the forming the first conductivity type region,
wherein the forming of the first conductivity type region and the forming of the control passivation layer are performed by an in-situ process.
7. The method of manufacturing a photovoltaic solar cell according to claim 1 , wherein the performing of the second dry etching to form the minute V-shaped protrusion uses sulfur hexafluoride gas, oxygen gas, and chlorine gas.
8. The method of manufacturing a photovoltaic solar cell according to claim 7 , wherein a volume ratio of the sulfur hexafluoride gas to the oxygen gas is 1 to 2.
9. The method of manufacturing a photovoltaic solar cell according to claim 7 , wherein a volume ratio of the chlorine gas to the oxygen gas is 0.2 to 1.
10. The method of manufacturing a photovoltaic solar cell according to claim 7 , wherein a volume ratio of the oxygen gas that is used when removing the first conductivity type region and the oxygen gas that is used when performing the second dry etching to form the minute V-shaped protrusion is 1.5 to 5.
11. The method of manufacturing a photovoltaic solar cell according to claim 1 , wherein before forming the first conductivity type region, a V-shaped protrusion is not formed on the one surface and is formed on the opposite surface among the one surface and the opposite surface of the single crystalline semiconductor substrate.
12. The method of manufacturing a photovoltaic solar cell according to claim 11 , wherein the forming of the v-shaped protrusion on the opposite surface of the single crystalline semiconductor substrate is performed by wet etching.
13. The method of manufacturing a photovoltaic solar cell according to claim 12 , wherein the minute V-shaped protrusion is formed on a surface of the V-shaped protrusion.
14. A method of manufacturing a photovoltaic solar cell, the method comprising;
forming a first conductivity type region that contains a first conductivity dopant, on one surface of a semiconductor substrate and an opposite surface that is opposite to the one surface;
performing a first dry etching to remove the first conductivity type region formed on the opposite surface of the semiconductor substrate and to remove an edge portion of the first conductivity type region formed on the one surface of the semiconductor substrate to provide an isolation, and performing a second dry etching continuously to form a minute V-shaped protrusion on the opposite surface of the semiconductor substrate; and
forming a second conductivity type region that contains a second conductivity dopant on the opposite surface of the semiconductor substrate,
wherein the first dry etching is performed by reactive ion etching (RIE) using sulfur hexafluoride gas oxygen gas,
wherein a volume ration of the sulfur hexafluoride gas to the oxygen gas is 3 to 5, and
wherein the minute V-shaped protrusion is further formed on an inclined portion of the first conductivity type region on the one surface of the semiconductor substrate, the inclined portion being a part that remained after the edge portion of the first conductivity type region that was removed by the first dry etching.