Modelling of device structure effects in backside illuminated CMOS compatible photodiodes

A backside illuminated CMOS photodiode consisting of an n+ (source implant) emitter and P-substrate base has been numerically simulated in a 1D approximation. The effects of device dimensions (junction depth and photodiode thickness), emitter and base dopant concentrations have been examined in relation to the spectral dependence of the quantum efficiency. The calculations indicate that greater control over the spectral response of the photodiode can be realised for a backside-illuminated photodiode, compared to the normal frontside illuminated structure of current Camera on a CMOS chip technology.