Method for manufacturing solar cell
A method for manufacturing a solar cell according to an embodiment of the present invention includes preparing a semiconductor substrate having a first conductivity type dopant; ion-implanting a pre-amorphization elements into a front surface of the semiconductor substrate to form an amorphous layer; and forming an emitter layer by ion-implanting second conductivity type dopant into the front surface of the semiconductor substrate. The method then further includes heat-treating the layers to activate the second conductivity type dopant. The method further includes forming a back surface field layer at a back surface of the semiconductor substrate by ion-implanting a first conductivity type dopant.
1. A method for manufacturing a solar cell, comprising:
preparing a semiconductor substrate having a first conductivity type dopant;
ion-implanting a pre-amorphization element into a front surface of the semiconductor substrate to form an amorphous layer; and
forming an emitter layer by ion-implanting a second conductivity type dopant into the front surface of the semiconductor substrate.
2. The method according to claim 1 , wherein the pre-amorphization element and the second conductivity type dopant are different from each other.
3. The method according to claim 2 , wherein the pre-amorphization element has an atomic number larger than that of the second conductivity type dopant.
4. The method according to claim 1 , wherein the pre-amorphization element comprises at least one element selected from the group consisting of carbon group elements and noble gas group elements.
5. The method according to claim 1 , wherein the pre-amorphization element comprises at least one of argon (Ar) and germanium (Ge).
6. The method according to claim 1 , wherein the semiconductor substrate has an n-type, and wherein the second conductivity type dopant comprises at least one of boron (B) and gallium (Ga).
7. The method according to claim 1 , wherein, in the ion-implanting of the pre-amorphization element, a dose of the pre-amorphization element is in a range of about 1×10 14 /cm 2 ˜3×10 15 /cm 2 , and
wherein, in the forming the emitter layer, a dose of the second conductivity type dopant is in a range of about 2×10 15 /cm 2 ˜2×10 15 /cm 2 .
8. The method according to claim 1 , wherein, after forming the emitter layer, the method further comprises:
heat-treating for activating the second conductivity type dopant, wherein, in the heat-treating, the second conductivity type dopant is diffused into the semiconductor substrate deeper than the pre-amorphization element.
9. The method according to claim 1 , wherein the emitter layer comprises a first layer including the pre-amorphization element and the second conductivity type dopant and a second layer including the second conductivity type dopant, without the pre-amorphization element, and
wherein a thickness ratio of the emitter layer to the first layer is 1:0.05˜1:0.15.
10. The method according to claim 8 , wherein, temperature of the heat-treating is in a range of about 400˜700° C.
11. The method according to claim 8 , further comprising, between the preparing the semiconductor substrate and the forming the emitter layer or between the forming the emitter layer and the heat-treating:
forming a back surface field layer at a back surface of the semiconductor substrate by ion-implanting the first conductivity type dopant into the back surface,
wherein, in the heat-treating, the emitter layer and the back surface field layer are simultaneously activated.
12. The method according to claim 11 , wherein the first conductivity type dopant comprises phosphorus (P).