Ge/SiGe multiple quantum well photodiode with 30 GHz bandwidth

We demonstrate high speed Ge/SiGe multiple quantum wells photodiodes using a surface-illuminated vertical p-i-n structure. The device, with a mesa diameter of 12 mu m, exhibits a low dark current of 231 nA at -1 V bias. An optical bandwidth of 10 and 26 GHz is measured at -1 and -4 V reverse bias, respectively, and reaches over 30 GHz at a reverse bias of -7 V. These results prove the suitability of Ge/SiGe multiple quantum well structures for high performance optoelectronic devices required for optical interconnection applications.