1064 nm photoresponse enhancement of femtosecond-laser-irradiated Si photodiodes by etching treatment

Abstract

We propose an etching treatment to improve the photoresponse of a femtosecond (fs)-laser-irradiated silicon photodiode working at 1064 nm. We investigated its surface structure and optical and electrical properties after fs laser irradiation, and further demonstrated the evolution of textured surface morphology, hyperdoping concentration, and crystallinity with etching time. We found that the etching treatment can peel off the hyperdoped layer by an appropriate amount, control the dopant concentration, and repair the crystallinity and subsurface damage of the hyperdoped microstructured silicon induced by fs laser irradiation. Experimental results indicate that the photoresponse at 1064 nm can be enhanced from 0.2 to 0.45 A/W after etching treatment.