Light effect in photoionization of traps in GaN MESFETs

TL;DR

This paper uses Monte Carlo simulations to study how trap centers in GaN MESFETs cause current collapse at low temperatures and how light-induced photoionization can recover the device performance, aligning well with experimental data.

Contribution

It introduces a simulation approach to analyze light effects on trap-induced current collapse in GaN MESFETs, providing insights into trap behavior and device recovery mechanisms.

Findings

Trap centers cause current collapse at low temperatures.

Light-induced photoionization increases drain current.

Simulation results agree with experimental data.

Abstract

Trapping of hot electron behavior by trap centers located in buffer layer of a wurtzite phase GaN MESFET has been simulated using an ensemble Monte Carlo simulation. The results of the simulation show that the trap centers are responsible for current collapse in GaN MESFET at low temperatures. These electrical traps degrade the performance of the device at low temperature. On the opposite, a light-induced increase in the trap-limited drain current, results from the photoionization of trapped carriers and their return to the channel under the influence of the built in electric field associated with the trapped charge distribution. The simulated device geometries and doping are matched to the nominal parameters described for the experimental structures as closely as possible, and the predicted drain current and other electrical characteristics for the simulated device including trapping center effects show close agreement with the available experimental data.