A high-speed lateral PIN polysilicon photodiode on standard bulk CMOS process

Abstract

This paper reports a lateral PIN polysilicon photodiode on standard bulk complementary metal-oxidesemiconductor (CMOS) process for monolithically integrated high-speed optoelectronic integrated circuits (OEIC). A nominal undoped polysilicon as the photodetection area is intentionally created without introducing any process modification. With the device area of 50×50μm2, a measured responsivity of 46mA/W and a quantum efficiency of 11% were observed under the reverse voltage of 10V and the wavelength of 520nm. A compact equivalent circuit model for the proposed lateral photodiode is built to analyze the frequency response, and a bandwidth of over 20GHz was obtained from the measured data, which is to the best of our knowledge the largest bandwidth ever reported based on standard bulk CMOS process.