ALUMINUM OXIDE PASSIVATION FOR SOLAR CELLS
The present application provides effective and efficient structures and methods for the formation of solar cell base and emitter regions and passivation layers using laser processing. Laser absorbent passivation materials are formed on a solar cell substrate and patterned using laser ablation to form 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.