Ge-on-Si Image Sensor with NIR Sensitivity

In a recent preprint ( https://arxiv.org/ftp/arxiv/papers/2209/2209.14242.pdf) Ponizovskaya-Devine et al. describe a new Ge-on-Si image sensor with enhanced sensitivity up to 1.7um for NIR applications.

Abstract

We present a Germanium “Ge-on-Si” CMOS image sensor with backside illumination for the near-infrared (NIR) electromagnetic waves (wavelength range 300–1700 nm) detection essential for optical sensor technology. The micro-holes help to enhance the optical efficiency and extend the range to the 1.7 µm wavelength. We demonstrate an optimization for the width and depth of the nano-holes for maximal absorption in the near infrared. We show a reduction in the cross-talk by employing thin SiO2 deep trench isolation in between the pixels. Finally, we show a 26–50% reduction in the device capacitance with the introduction of a hole. Such CMOS-compatible Ge-onSi sensors will enable high-density, ultra-fast and efficient NIR imaging.

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