Impact of ALD HfO2 Gate-Oxide Geometries on the Electrical Properties and Single-Event Effects of beta-Ga2O3 MOSFETs: A Simulation Study

Abstract

A Sentaurus TCAD 2-D model of beta-Ga(2)O(3)metal-oxide semiconductor field-effect transistors (MOSFETs) with a polycrystalline HfO(2)gate-oxide deposited using atomic layer deposition (ALD), which has a semiconductor-on-insulator (SOI) structure, is developed. The results of model shows good agreement with the DC and the AC characteristics of the fabricated device by incorporating proper parameters for the materials, as well as the device models. We also investigate and compare electrical performance of the devices with modified HfO(2)gate-oxide geometries. With a reduced HfO(2)coverage over the channel, the transconductance (g(m)) is enhanced, the threshold voltage (Vth) shifts toward a positive voltage, both of which are advantageous for device applications. Moreover, radiation effects during transient operation of the beta-Ga2O3MOSFETs are evaluated and compared for the fabricated and the modified oxide geometries by incorporating carrier generation models with heavy-ions and alpha particles.