High Photoresponsivity Germanium Nanodot PhotoMOSFETs for Monolithically-Integrated Si Optical Interconnects

Abstract

We presented a self-organized, MOS gate-stacking structure of SiO2/Ge-dot/SiO2/Si1-xGex-shell, using thermal oxidation of poly-Si0.85Ge0.15 nanopillars over buffer Si3N4 on the Si substrate, for the fabrication of high performance Ge-dot photoMOSFETs. Low dark current of 3 mu A/.m(2), Superior high photoresponsivity of 1400. 710A/W, and short response time of <0.8ns are measured on 90nm Ge-dot photoMOSFETs with W/L = 70 mu m/3 mu m under 850nm-1550nm illumination, providing a practically-achievable, core building block for monolithically-integrated Si optical interconnects.