High-k HfO2-Based AlGaN/GaN MIS-HEMTs with Y2O3 Interfacial Layer for High Gate Controllability and Interface Quality

Abstract

High- {k} HfO2 has been widely adopted in Si based MOSFETs as gate dielectric for the superior control over gate leakage and channel electrostatics. However, in AlGaN/GaN HEMTs, the additional interface issue as well as high oxygen transparency of HfO2 has hindered its practical applications. In this work, high- {k}~text{Y}{2}text{O}{3} with ultra-low oxygen permeability and high thermodynamic robustness has been introduced as the interfacial layer between HfO2/GaN for the interface engineering. It has been demonstrated that, the HfO2/Y2O3 gate dielectric stacks have obtained the GaN MIS-HEMT an ultra-small subthreshold swing of 70 mV/decade, an extremely low gate leakage of 10-12 A/mm, and a desirable dielectric/semiconductor interface quality with interface state density in level of 1012 cm-2eV-1. Meanwhile, a maximum drain current of 600mA/mm has been achieved together with an on-state resistance ( {R} {mathrm{ on}} ) of 10.7 {Omega }cdot mm and a specific {R} {mathrm{ on}} of 2.62 text{m}{Omega }cdot cm2.