CMOS-compatible, waveguide-integrated Ge metal-semiconductor-metal photodetectors

摘要

We demonstrate Ge metal-semiconductor-metal (MSM) photodetectors monolithically integrated with silicon-oxynitride (SiO_xN_y) waveguides. Ge photodetector layer was epitaxially grown by an UHVCVD system and the waveguide was formed on top of the Ge photodetector by PECVD. The entire process is found to be completely compatible with the standard CMOS process. Light is evanescently coupled from silicon-oxynitride (SiO_xN_y) waveguide to the underlying Ge photodetector, achieving at 2 V a responsivity of 0.33 A/W at 1.55 μm wavelength and a dark current of 1 μk for a 10 μm long photodetector.