Solar cell and method for manufacturing the same
View Patent ↗A solar cell according to an embodiment of the invention includes a substrate of a first conductive type, an emitter region of a second conductive type opposite the first conductive type, which is positioned at the substrate, an anti-reflection layer including a first opening exposing the emitter region and a plurality of second openings which expose the emitter region and are separated from one another, a first electrode which is positioned on a first portion of the emitter region exposed through the first opening and is connected to the first portion, a first bus bar which is positioned on a second portion of the emitter region exposed through the plurality of second openings and is connected to the second portion and the first electrode, and a second electrode which is positioned on the substrate and is connected to the substrate.
1. A method for manufacturing a solar cell comprising:
doping impurities of a first conductive type or impurities of a second conductive type opposite the first conductive type on a first surface of a semiconductor substrate of the first conductive type to form an impurity region;
forming a passivation layer on the impurity region;
forming an impurity layer of the same conductive type as the impurity region on the passivation layer;
selectively irradiating a laser beam onto the impurity layer to form a first opening exposing a first portion of the impurity region and a plurality of second openings, which are separated from the first opening and expose a second portion of the impurity region, in the passivation layer; and
forming an electrode on the first portion of the impurity region exposed through the first opening and forming a bus bar on the second portion of the impurity region exposed through the plurality of second openings, the bus bar being connected to the electrode,
wherein the laser beam is selectively irradiated onto the impurity layer,
wherein a portion of the impurity region underlying the passivation layer becomes a first impurity region having a first sheet resistance,
wherein the first and second portions of the impurity region exposed through the first opening and the plurality of second openings become a second impurity region having a second sheet resistance less than the first sheet resistance, and
wherein the second impurity region is formed by diffusing impurities of the impurity layer into the impurity region during the selectively irradiating of the laser beam onto the impurity layer to form the first opening and the plurality of second openings.
2. The method of claim 1 , wherein a width of the first opening is substantially equal to a width of each of the plurality of second openings.
3. The method of claim 1 , wherein the plurality of second openings are separated from one another at uniform intervals.
4. The method of claim 3 , wherein a distance between two adjacent second openings is about 15 μm to 30 μm.
5. The method of claim 1 , wherein the plurality of second openings are separated from one another at different intervals.
6. The method of claim 5 , wherein a distance between two adjacent second openings is about 15 μm to 30 μm.
7. The method of claim 1 , wherein the electrode and the bus bar are simultaneously formed using a plating method.