A strained SiGe layer heterojunction bipolar phototransistor for short-range opto-microwave applications

A strained-SiGe heterojunction bipolar phototransistor is presented for the first time. Theoretical demonstration of the device is recalled. Practical measurements at 940 nm are presented. A dc phototransistor mode responsivity of 1.49 A/W is achieved. Tools are proposed for the opto-microwave behavior analyses of photodetectors. A frequency behavior reaching 32 GHz with a -70 dBm output level and a 200 /spl mu/W input optical power is demonstrated.