Comparative Study of the Resolution of Ge-on-Si Photodetectors for 1μ m Infrared Signals

Abstract

Most of the studies on narrow-band near-infrared detection reported so far are related to the 1.3μm and 1.55μm spectral windows. There is insufficient research work done on radiation detection in the narrow band around 1 μm wavelength, which is just outside the Si (0.95μ m) and GaAs (0.85μ m) effective cut-off spectral sensitivity. This paper presents a p+n Ge-on-Si detector with a customized large active window, employing the PureGaB technology, to detect radiation in a very narrow band around 1μ m. The advantages of the proposed detector are: (1) CMOS-compatibility and micro-spectroscopic capability; (2) low dark current and high photoresponsivity, compared to similar devices reported in the literature; (3) enhanced sensitivity to weak radiation by realizing an ultra-shallow and very thin depletion region. These detectors can be good candidates for measuring the YAG laser radiation and measuring stray radiation in photolithography.