High-speed metal-germanium-metal configured PIN-like Ge-photodetector under photovoltaic mode and with dopant-segregated Schottky-contact engineering

Abstract

In this letter, we present a high-speed metal-germanium-metal configured Ge-photodetectors (MGM-PDs) under photovoltaic mode (i.e., 0-V operation). The metal contacts are engineered by an asymmetrical (i.e., boron and arsenic) dopant-segregation scheme on Schottky-contacts to suppress the dark current, and are with scaled spacing (∼0.8 μm). The MGM-PD (with ∼300-nm-thick Ge) is integrated on a silicon-on-isolator waveguide with complementary metal-oxide-semiconductor field effect transistor compatible process. For λ = 1550 nm, under 0-V bias, the devices illustrate a reasonable responsivity ∼0.17 A/W and a fast pulse response of 18 ps. © 2008 IEEE.