Modelling of device structure effects on electrical crosstalk in back illuminated CMOS compatible photodiodes

Abstract

Standard CMOS fabrication processes provide the means to realize the further development of back illuminated photodiode arrays for imaging systems. We have simulated crosstalk effects in a back illuminated CMOS compatible photodiode array, and compared this effect with that predicted for front illuminated arrays, using a two dimensional simulation model. It was found that the crosstalk in back illuminated arrays is generally greater than that for front illuminated arrays with identical structure, although this effect can be reduced by decreasing the thickness of the array. The n-well junction depth had little effect on the crosstalk predicted for the back illuminated case.