Method for treating a stack obtained during the manufacture of a heterojunction photovoltaic cell
View Patent ↗A method for treating a stack includes a substrate of n-doped crystalline silicon and a passivation layer of hydrogenated amorphous silicon disposed on a face of the substrate, the method including exposing the stack to electromagnetic radiation during a treatment period (t) less than or equal to 12 s, the electromagnetic radiation having an irradiance (E) greater than or equal to 200 kW/m 2 .
1. A method for treating a stack comprising a substrate of n-doped crystalline silicon and a passivation layer of hydrogenated amorphous silicon disposed on a face of the substrate, said method comprising exposing the stack to electromagnetic radiation during a treatment period (t) less than or equal to 8 s, the electromagnetic radiation having an irradiance (E) greater than or equal to 300 kW/m 2 .
2. The method according to claim 1 , wherein the irradiance (E) of the electromagnetic radiation is greater than or equal to 1000 kW/m 2 and wherein the treatment period (t) is less than or equal to 2.5 s.
3. The method according to claim 1 , wherein the treatment period (t) is inversely proportional to the irradiance (E).
4. The method according to claim 1 , wherein the electromagnetic radiation is monochromatic and has a wavelength (λ) comprised between 400 nm and 1100 nm.
5. The method according to claim 4 , wherein the treatment period (t) satisfies the following relationship:
t
≥
0
.
2
3
×
1
0
0
0
E
×
9
8
0
λ
where λ is the wavelength of the electromagnetic radiation and E is the irradiance of the electromagnetic radiation.
6. The method according to claim 5 , wherein the treatment period (t) furthermore satisfies the following relationship:
t
≤
1
0
0
0
E
×
9
8
0
λ
.
7. The method according to claim 1 , wherein the electromagnetic radiation comprises several components with a wavelength comprised between 400 nm and 1100 nm.
8. The method according to claim 7 , wherein the treatment period (t) satisfies the following relationship:
t
≥
0
.
2
3
×
1
∑
i
=
1
n
E
i
1
0
0
0
×
λ
1
9
8
0
where i is an index that varies between 1 and the number n of components of the electromagnetic radiation, λ i is the wavelength of the component of index i and E i is the irradiance of the component of index i.
9. The method according to claim 8 , wherein the treatment period (t) furthermore satisfies the following relationship:
t
≤
1
∑
i
=
1
n
E
i
1
0
0
0
×
λ
1
980
.
10. The method according to claim 1 , wherein the exposing of the stack to the electromagnetic radiation is continuous or sequential.
11. The method according to claim 1 , wherein the exposing of the stack to the electromagnetic radiation comprises a plurality of phases of exposing of the stack with a period less than or equal to 0.2 s, separated by phases of cooling, and wherein the stack is maintained at a temperature less than or equal to 320° C. during each one of the phases of exposure.
12. The method according to claim 1 , wherein the substrate has a concentration in doping impurities of the acceptor type less than 10 13 cm −3 .
13. A method for treating a stack comprising a substrate of n-doped crystalline silicon and a passivation layer of hydrogenated amorphous silicon disposed on a face of the substrate, said method comprising exposing the stack to electromagnetic radiation during a treatment period (t) less than or equal to 12 s, the electromagnetic radiation having an irradiance (E) greater than or equal to 200 kW/m 2 , wherein the stack is maintained at a temperature less than 200° C. during the exposing of the stack to electromagnetic radiation.
14. A method for manufacturing a heterojunction photovoltaic cell, comprising:
forming a stack by depositing a passivation layer of hydrogenated amorphous silicon on a face a of a substrate of n-doped crystalline silicon;
exposing the stack to electromagnetic radiation during a treatment period (t) less than or equal to 8 s, the electromagnetic radiation having an irradiance (E) greater than or equal to 300 kW/m 2 .
15. The method according to claim 14 , further comprising depositing a doped amorphous silicon layer on the passivation layer.
16. The method according to claim 15 , wherein the stack is exposed to the electromagnetic radiation during the deposition of the doped amorphous silicon layer.
17. The method according to claim 15 , further comprising depositing a transparent conductive oxide layer on the doped amorphous silicon layer.
18. The method according to claim 17 , wherein the stack is exposed to electromagnetic radiation during the depositing of the transparent conductive oxide layer.
19. The method according to claim 17 , further comprising forming at least one electrode on the transparent conductive oxide layer, the forming of said at least one electrode comprising an operation of depositing by screen printing a metal paste and an operation of hardening the metal paste, and wherein the operation of hardening the metal paste and the exposing to the electromagnetic radiation are accomplished simultaneously.