Single Micro-hole per Pixel for Thin Ge-on-Si Image Sensor with Enhanced Sensitivity upto 1700 nm

TL;DR

This paper introduces a Ge-on-Si CMOS image sensor with micro-holes that significantly enhances near-infrared sensitivity up to 1700 nm, reduces cross-talk and capacitance, enabling high-density and fast imaging.

Contribution

The study presents a novel micro-hole design in Ge-on-Si sensors that improves infrared absorption, reduces device capacitance, and minimizes cross-talk, advancing near-infrared imaging technology.

Findings

Enhanced absorption at 1700 nm due to optimized micro-holes

26-50% reduction in device capacitance

Reduced cross-talk with deep trench isolation

Abstract

We present a Ge-on_Si CMOS image sensor with backside illumination for the near-infrared electromagnetic waves, wavelengths range 300-1700nm, detection essential for optical sensor technology. The micro-holes help to enhance the optical efficiency and extend the range to the 1.7 microns 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 cross-talk by employing thin Si oxide deep trench isolation in between the pixels. Finally, we show a 26-50 percent reduction in the device capacitance with the introduction of a hole. Such CMOS-compatible Ge-on_Si sensor will enable high-density, ultra-fast and efficient near-infrared imaging.