Method of diffusing impurity-diffusing component and method of manufacturing solar cell
A method of diffusing an impurity-diffusing component including forming a first diffusing agent layer containing a first conductivity type impurity-diffusing component on the surface of a semiconductor substrate; calcining the first diffusing agent layer; forming a second diffusing agent layer containing a second conductivity type impurity-diffusing component on the surface of the semiconductor substrate excluding the region where the first diffusing agent layer is formed; and heating the semiconductor substrate at a temperature higher than the calcination temperature to diffuse the first and second conductivity type impurity-diffusing components to the semiconductor substrate.
1. A method of diffusing an impurity-diffusing component comprising:
forming a first diffusing agent layer containing a first conductivity-type impurity diffusing component on the surface of a semiconductor substrate;
calcining the first diffusing agent layer when the first diffusing agent layer is formed on the surface of the semiconductor substrate and while a second diffusing agent layer containing a second conductivity-type impurity diffusing component is not yet formed;
forming the second diffusing agent layer on the surface of the semiconductor substrate excluding a region where the first diffusing agent layer is formed; and
heating the semiconductor substrate at a temperature higher than a calcination temperature to diffuse the first conductivity-type impurity diffusing component and the second conductivity-type impurity diffusing component into the semiconductor substrate.
2. The method of diffusing an impurity-diffusing component according to claim 1 , wherein the first conductivity type is boron, and the second conductivity type is phosphorus.
3. The method of diffusing an impurity-diffusing component according to claim 1 , wherein the first diffusing agent layer and the second diffusing agent layer are formed on the same surface of the semiconductor substrate.
4. The method of diffusing an impurity-diffusing component according to claim 1 , wherein, in the calcining, the first diffusing agent layer is heated at a temperature of 500° to 900° C.
5. The method of diffusing an impurity-diffusing component according to claim 1 , wherein the first diffusing agent layer is formed using a P-type diffusing agent composition.
6. The method of diffusing an impurity-diffusing component according to claim 5 , wherein the P-type diffusing agent composition contains borate ester and an alkoxy silane compound (C).
7. The method of diffusing an impurity-diffusing component according to claim 6 , wherein the P-type diffusing agent composition further comprises a polyhydric alcohol (B).
8. The method of diffusing an impurity-diffusing component according to claim 7 , wherein the polyhydric alcohol (B) is represented by Formula (2) below.
wherein k represents an integer of 0 to 3, m represents an integer of 1 or more, R 2 and R 3 independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 1 to 5 carbon atoms, when there are a plurality of R 2 s and a plurality of R 3 s, the plurality of R 2 s and the plurality of R 3 s may be the same or different, when k is 2 or more, the plurality of R 2 s and the plurality of R 3 s necessarily include at least one hydroxyl group or a hydroxyalkyl group having 1 to 5 carbon atoms, and R 4 and R 5 independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
9. The method of diffusing an impurity-diffusing component according to claim 7 , wherein the concentration of metal impurities contained in the P-type diffusing agent composition, except for metallic components contained in the borate ester, the polyhydric alcohol (B), and the alkoxy silane compound (C), is 500 ppb or less.
10. The method of diffusing an impurity-diffusing component according to claim 1 , wherein the second diffusing agent layer is formed using an N-type diffusing agent composition.
11. The method of diffusing an impurity-diffusing component according to claim 10 , wherein the N-type diffusing agent composition contains an impurity-diffusing component (A2) and an alkoxy silane compound (C).
12. The method of diffusing an impurity-diffusing component according to claim 11 , wherein the impurity-diffusing component (A2) includes a compound of an element of Group V (Group 15).
13. A method of manufacturing a solar cell comprising:
using a method of diffusing an impurity-diffusing component comprising:
forming a first diffusing agent layer containing a first conductivity-type impurity diffusing component on the surface of a semiconductor substrate; calcining the first diffusing agent layer when the first diffusing agent layer is formed on the surface of the semiconductor substrate and while a second diffusing agent layer containing a second conductivity-type impurity diffusing component is not yet formed; forming the second diffusing agent layer on the surface of the semiconductor substrate excluding a region where the first diffusing agent layer is formed; and heating the semiconductor substrate at a temperature higher than a calcination temperature to diffuse the first conductivity-type impurity diffusing l the second conductivity-type impurity diffusing component into the semiconductor substrate, to form a first conductivity-type first impurity diffusion layer and a second conductivity-type second impurity diffusion layer on the surface of the semiconductor substrate by diffusing the first conductivity-type impurity diffusing component and the second conductivity-type impurity diffusing component into the semiconductor substrate; and
forming a first electrode and a second electrode on the surface of the semiconductor substrate, electrically connecting the first electrode to the first impurity diffusion layer, and electrically connecting the second electrode to the second impurity diffusion layer.