Advances in the field of poly-Ge on Si near infrared photodetectors

The fabrication and characterization of near infrared photodetectors integrated on silicon substrates are reported on where the active layer is a thermally evaporated polycrystalline germanium. Recent results are presented in the effort to enhance the optoelectronic properties of the poly-Ge film in terms of uniformity for multiple device integration, speed and responsivity. In particular we demonstrate a 16 pixel linear array, a speed of photoresponse of about 650 ps and an enhancement of responsivity by a factor of four. The fabrication process, including substrate cleaning and preparation, requires temperatures lower than 300°C being fully compatible with silicon technology.