Enhancement of Photodetector Responsivity in Standard SOI CMOS Processes by introducing Resonant Grating Structures

M Auer,K.-H Brenner

doi:10.2971/jeos.2011.11014

Abstract

A new photodetector concept is described which is fully compatible with the standard SOI CMOS process and does not require any post-processing steps. Our simulations are based on two-dimensional RCWA (Rigorous Coupled Wave Analysis) and local absorption theory (K.-H.Brenner, "Aspects for calculating local absorption with the rigorous coupled-wave method" Optic Express 2010, accepted). The simulations show that optimized lateral grating structures are able to enhance the absorption efficiency of thin semi-conductor detectors by a factor of 32 compared to nonenhanced approaches.

Highlights

In order to optimise the design of photodetectors, photovoltaic elements or photolithographic setups, it is a common procedure to simulate intensity distributions
A common way to describe absorption is based on the Lambert Beer law, which only applies to homogeneous volumes
The present paper demonstrates a new concept of a photodetector design [3], which is based on simulation results with the local absorption theory

Summary

INTRODUCTION

In order to optimise the design of photodetectors, photovoltaic elements or photolithographic setups, it is a common procedure to simulate intensity distributions. Based on RCWA (Rigorous Coupled Wave Analysis), which provides the electromagnetic field distribution for structured volumes, a method to calculate local absorption was presented in [1]. The present paper demonstrates a new concept of a photodetector design [3], which is based on simulation results with the local absorption theory. This photodetector is designed for a wavelength of 850 nm and is fully compatible with the standard SOI CMOS process eliminating the need for any post-processing steps. The fabrication process ends up with a very compact design

LOCAL ABSORPTION THEORY

PHOTODETECTOR DESIGN

CONCLUSION