Comparative Study of the Resolution of Ge-on-Si Photodetectors for $1\ \mu \mathrm{m}$ Infrared Signals

Most of the studies on narrow-band near-infrared detection reported so far are related to the $\mathbf{1}.\mathbf{3}\ \boldsymbol{\mu}\mathbf{m}$ and $\mathbf{1}.\mathbf{55}\ \boldsymbol{\mu}\mathbf{m}$ spectral windows. There is insufficient research work done on radiation detection in the narrow band around $1 \mu\mathrm{m}$ wavelength, which is just outside the Si $(\mathbf{0}.\mathbf{95}\ \boldsymbol{\mu} \mathbf{m})$ and GaAs $(\mathbf{0}.\mathbf{85}\ \boldsymbol{\mu} \mathbf{m})$ 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 $\mathbf{1}\ \boldsymbol{\mu} \mathbf{m}$ . 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.