A high-speed silicon metal-semiconductor-metal photodetector fully integrable with (Bi)CMOS circuits

Abstract

The authors have fabricated and characterized interdigitated silicon metal-semiconductor-metal photodetectors (MSM-PDs) using a self-Aligned PtSi Schottky barrier metallurgy and SiO2 passivation in a VLSI-compatible process. These MSM-PDs are optimal for high speed applications at wavelengths <700 nm. The detectors show a classic Si spectral response with a 3 dB cut-off frequency in excess of 1.1 GHz at a wavelength of 630 nm. DC responsivities in excess of 0.3 A/W were measured on devices with a PtSi electrode spacing of 1.6 mu m and a total device area of 6375 mu m2 of which 46% was active. The integrated detectors have potential applications in short-wavelength optical interconnects and optical storage systems.