Investigating the suitability of using avalanche photodiodes or non-standard photodetectors as colour sensors

Abstract

In the era of information, sensors are omnipresent, and high-performance sensors are crucial for the development of the Internet of Things. Humans require various sensors to detect signals from nature in their surroundings. Particularly, optical information is one of the most essential signals in the natural world, with color being one of its most common attributes. The demand for advanced color sensing capabilities has surged across various fields such as image recognition, machine vision, and industrial automation. As a result, high-performance color sensors have garnered the attention of researchers worldwide. Currently, there are numerous types of color sensors available, but traditional color sensors based on RGB filters or spectral sensors have limitations in terms of cost, complexity, and size. In order to explore alternative solutions, this study delves into a comprehensive assessment of the feasibility of utilizing avalanche photodiodes (APDs) as potential color sensors. Ensuring precise detection and achieving balanced trichromatic sensing is of paramount importance, and this forms the objective of this research project. Due to their compatibility with CMOS processes, high single-photon sensitivity, low noise, and the trend toward miniaturization, silicon-based APD color sensors could be alternative, more sensitive, devices for color sensing. In this research endeavor, a novel APD color sensor capable of simultaneous RGB detection is designed. The fundamental structural parameters are initially calculated using MATLAB, and subsequent doping concentrations for each layer are determined based on these parameters. To establish the fabrication process, the production of the APD sensor is simulated using TSUPREME-4, with the confirmation of process conditions. The electrical characterization of the APD color sensor is performed using Medici. Ultimately, through the validation of TCAD simulation results, the design of the APD color sensor is confirmed to operate as intended.