GeSn on Si avalanche photodiodes for short wave infrared detection

摘要

A mesa-type normal incidence separate-absorption-charge-multiplication (SACM) Ge_(0.95)Sn_(0.05)/Si avalanche photodiode (APD) was fabricated. The 60-μm-diameter avalanche photodiode achieved a responsivity of ~5A/W (gain=24) and ~3.1A/W (gain=20) at 98% breakdown voltage (-14.2V) under 1310nm and 1550nm illumination respectively with a low dark current of 10μA. The -3 dB bandwidth for a 60-μm-diameter APD is about l-1.25GHz for gains from 5 to 20, resulting in a gain-bandwidth product of 25GHz for a C-band communication wavelength of 1550nm.