Solar cell, method of forming emitter layer of solar cell, and method of manufacturing solar cell

1. A solar cell, comprising:

a substrate of a first conductive type;

an emitter layer that is positioned on the substrate and is a second conductive type that is opposite to the first conductive type;

first electrodes that are connected to the emitter layer; and

a second electrode that is connected to the substrate,

wherein the emitter layer comprises a first emitter portion and a second emitter portion,

the first electrodes comprise a finger electrode, and a bus electrode intersecting and connected to the finger electrode, the first emitter portion and the second emitter portion are positioned under the bus electrode,

the plurality of finger electrodes and the plurality of bus electrode are formed on a surface of the substrate and are coplanar, and

the plurality of first emitter portions extend from the surface of the substrate to a first doped depth, and the plurality of second emitter portions extend from the surface of the substrate to a second doped depth that is different from the first doped depth.

2. The solar cell of claim 1 , wherein the second emitter portion has an impurity concentration that is more than an impurity concentration of the first emitter portion.

3. The method of claim 1 , wherein the second emitter portion has an impurity doped depth that is more than an impurity doped depth of the first emitter portion.

4. The solar cell of claim 1 , wherein the second emitter portion has a thickness more than a thickness of the first emitter portion.

5. The solar cell of claim 1 , further comprising an anti-reflection layer positioned on the emitter layer.

6. A solar cell, comprising:

a substrate of a first conductive type;

an emitter layer that is positioned on the substrate and is a second conductive type that is opposite to the first conductive type;

first electrodes that are connected to the emitter layer; and

a second electrode that is connected to the substrate,

wherein the emitter layer comprises a plurality of first emitter portions and a plurality of second emitter portions,

the first electrodes comprise a plurality of finger electrodes, and a plurality of bus electrodes intersecting and connected to the plurality of finger electrodes,

the plurality of bus electrodes are formed over alternate ones of the plurality of first emitter portions and the plurality of second emitter portions,

the plurality of finger electrodes and the plurality of bus electrode are formed on a surface of the substrate and are coplanar, and

the plurality of first emitter portions extend from the surface of the substrate to a first doped depth, and the plurality of second emitter portions extend from the surface of the substrate to a second doped depth that is different from the first doped depth.

7. The solar cell of claim 6 , wherein the plurality of second emitter portions have an impurity concentration that is more than an impurity concentration of the plurality of first emitter portions.

8. The solar cell of claim 6 , wherein the plurality of second emitter portions have an impurity doped depth that is more than an impurity doped depth of the plurality of first emitter portions.

9. The solar cell of claim 6 , wherein the plurality of second emitter portions have a thickness more than a thickness of the plurality of first emitter portions.

10. The solar cell of claim 6 , further comprising an anti-reflection layer positioned on the emitter layer.