Effect of rapid thermal annealing on DC performance of Mg_0.30Zn_0.70O/Cd_0.15Zn_0.85O MOSHFET

Abstract

This study focuses on a cost-effective method for fabrication of a metal oxide semiconductor-heterostructure field effect transistor (MOSHFET) based on MgZnO/CdZnO (MCO) using dual ion beam sputtering (DIBS), in contrast to the more expensive epitaxial growth system. The MOSHFETs developed in this research exhibit notable characteristics, such as a such as a substantial two-dimensional electron gas (2DEG) transconductance (~2.6 mS), a high ION/IOFF response ratio in the order of 108, and minimal gate leakage current. Furthermore, we explore the impact of rapid thermal annealing (RTA) on the drain current at various temperatures (600 and 800 ℃). The results indicate a fourfold improvement in drain current compared to unannealed conditions, primarily attributed to reduced contact resistance and no degradation in term of MgZnO/CdZnO structure. Additionally, an analysis of post-RTA treatment under a nitrogen (N2) atmosphere on gate leakage current is presented. The investigation spans temperatures ranging from 400 to 800 ℃, revealing that above 600 ℃ (gate leakage at 400 to 600 ℃ is around ~10-9 A), gate leakage in HFET is augmented by one order of magnitude (~10-8 A) due to a phase change in the dielectric. These findings underscore the feasibility of DIBS-grown MCO MOSHFETs as an economical solution for the mass production of switching devices and sensors.