LASER PROCESSING FOR SOLAR CELL BASE AND EMITTER REGIONS

1 . A method for processing a solar cell, comprising:

depositing a doped laser absorbent passivation layer on the surface of a solar cell substrate, said doped laser absorbent passivation layer having a doping opposite said solar cell substrate;

patterning said doped laser absorbent passivation layer using laser ablation; and

annealing said solar cell to form diffused solar cell doped regions corresponding to said doped laser absorbent passivation layer.

2 . The method of claim 1 , wherein said doped laser absorbent passivation layer is an oxygen rich doped laser absorbent passivation layer.

3 . The method of claim 1 , wherein said doped laser absorbent passivation layer is an metal rich doped laser absorbent passivation layer

4 . The method of claim 1 , wherein said doped laser absorbent passivation layer is aluminum oxide.

5 . The method of claim 4 , wherein said doped laser absorbent passivation aluminum oxide layer has a thickness in the range of 10 to 50 nm.

6 . The method of claim 1 , wherein said laser ablation has a wavelength in the IR to UV range.

7 . The method of claim 1 , wherein said laser ablation has a pulse width in the range of 1 to 100 nanoseconds.

8 . A method for processing a solar cell, comprising:

depositing a first doped oxygen rich non-densified aluminum oxide layer on the backside surface of a solar cell substrate, said first doped oxygen rich non-densified aluminum oxide layer having a doping opposite said solar cell substrate;

patterning said first doped oxygen rich non-densified aluminum oxide layer using laser ablation to define field emitter regions;

depositing a second doped oxygen rich non-densified aluminum oxide layer on the backside surface of a solar cell substrate, said second doped oxygen rich non-densified aluminum oxide layer having a doping opposite said solar cell substrate;

patterning said second doped oxygen rich non-densified aluminum oxide layer using laser ablation to define selective emitter regions;

depositing a third doped oxygen rich non-densified aluminum oxide layer on the backside surface of a solar cell substrate, said third doped oxygen rich non-densified aluminum oxide layer having a doping the same as said solar cell substrate;

laser ablating said third doped oxygen rich non-densified aluminum oxide layer to form base regions, said laser ablation; and

annealing said solar cell substrate to form base and emitter regions of said solar cell.

9 . The method of claim 8 , wherein said deposition of said first doped oxygen rich non-densified aluminum oxide and said second doped oxygen rich non-densified aluminum oxide is performed by an atmospheric pressure chemical vapor deposition process.

10 . The method of claim 8 , wherein said laser ablation has a wavelength in the IR to UV range.

11 . The method of claim 8 , wherein said laser ablation has a pulse width in the range of 1 to 100 nanoseconds.

12 . The method of claim 8 , wherein said first doped oxygen rich non-densified aluminum oxide layer and said second oxygen rich non-densified aluminum oxide layer are boron doped and said third doped oxygen rich non-densified aluminum oxide layer is phosphorus doped.

13 . A method for processing a solar cell, comprising:

depositing a first doped oxygen rich non-densified aluminum oxide layer on the backside surface of a solar cell substrate, said first doped oxygen rich non-densified aluminum oxide layer having a doping opposite said solar cell substrate;

patterning said first doped oxygen rich non-densified aluminum oxide layer using laser ablation to define field emitter regions;

depositing a second doped oxygen rich non-densified aluminum oxide layer on the backside surface of a solar cell substrate, said second doped oxygen rich non-densified aluminum oxide layer having a doping the same as said solar cell substrate;

laser ablating said second doped oxygen rich non-densified aluminum oxide layer to form base regions, said laser ablation; and

annealing said solar cell substrate to form base and emitter regions of said solar cell.

14 . The method of claim 13 , wherein said deposition of said first doped oxygen rich non-densified aluminum oxide and said second doped oxygen rich non-densified aluminum oxide is performed by an atmospheric pressure chemical vapor deposition process.

15 . The method of claim 13 , wherein said laser ablation has a wavelength in the IR to UV range.

16 . The method of claim 13 , wherein said laser ablation has a pulse width in the range of 1 to 100 nanoseconds.