Studying the effect of mobility models using TCAD simulation on the performance of AlGaN/AlN metal semiconductor metal metector

Abstract

The present work analyses the fundamental transport property of photogenerated carriers named low field mobility for Al0.5Ga0.5N/AlN/Sapphire-based MSM detector using five conventional mobility models. Using Atlas- Silvaco TCAD simulator, appropriate mobility models for differently doped structures were investigated for the least dark current density and improved photocurrent. For each doping case, low electric field mobility models have been compared for I-V characteristics, conduction current density, recombination rate, velocity and mobility of charge carriers. Since there are uncertainties for the most fundamental transport property like field-dependant mobility, therefore more study is required to model mobility for high performance of Wide Band Gap materials. In this work, the mobilities of carriers (mup and mun values) are not specified manually in the Silvaco simulation program however mobility model has been defined. The present work analyses various mobility models on dark current density, photocurrent, mobility and velocity of charge carriers in a photo-absorbent layer. Earlier experimental and theoretical studies have proved that variation in dark current density is greatly affected by doping concentration, structural dimension parameters and optical and electrical properties of detector’s materials. The main objective of the present work is selecting the suitable mobility model to get high Conduction current density in light to Conduction current density in dark ratio for each doping case. We also found that selection of models has a significant impact on spectral response. This simulation work could help align theoretical performance with experimental data and utilising AlGaN MSM detectors in modern UV detection and low noise applications.