Simulation study on electrical performance of passivated backgated graphene field effect transistor under electron radiation environment

Abstract

The back-gated Graphene Field-Effect Transistor (GFET) is commonly used in sensing applications including radiation detection, where a graphene channel is directly exposed to radiation beam that may degrade GFET’s performance. Passivating the device may reduce radiation defects and improve its electrical performance. Most of reported works presenting on ion irradiation on the top-gated GFET simulation study can provide initial results guideline to the future experimental work. The electrical performance of the passivated backgated GFETs under high exposure electron beam largely unknown. The electron beam radiation is of particular interest due to cleaner method and less harmful to the material. In this study, the impact of electron beam radiation on the performance of passivated GFETs is investigated using the Silvaco TCAD. An optimized backgated GFET with a passivation layer exhibiting an ambipolar behaviour of the graphene is simulated under radiation doses of 50, 100 and 200 kGy, similar range doses from experimental work for easier comparison and validation. Three common passivation materials namely SiO2, Si3N4, and Al2O3 being incorporated into the radiation simulation of passivated GFETs and comparatively evaluated. These materials demonstrate notable performance as a passivation layer based due to their radiationhardened properties and their ability to adverse effects of radiation. The results demonstrate that the SiO2-passivated GFET exhibits the highest conductivity with minimal radiation defect. In contrast, Si3N4 and Al2O3-passivated GFETs show slightly lower performances due to higher radiation-induced hole trapping mechanism. Additionally, a hole trapping mechanism is proposed in this study which explain in detail the reasons of different performance of non-passivated and passivated GFET under high energy electron radiation. The passivation layer has been proven to effectively maintain the GFET electrical performance with minimal defects particularly with SiO2 due to lower dangling bond This study validates the simulation framework and demonstrates the capability of tool to perform the radiation simulation on the twodimensional material-based devices.