Geometry Dependence of CMOS-Compatible, Polysilicon, Leaky-Mode Photodetectors

Complementary metal-oxide-semiconductor-compatible metal-semiconductor-metal polysilicon photodiodes fabricated in a commercial 0.35-mum technology offer estimated responsivities of up to 0.35 A/W at 654 nm. An effective absorption coefficient of 0.63 dB/mum was extracted from responsivities for 5- to 10-mum-long waveguide-coupled detectors. Increasing responsivity at smaller contact spacing indicated a two-part photocurrent response, with secondary photocurrent dominating at small contact spacings and high electric fields