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

摘要

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 Y2O3 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 similar to 70 mV/decade, an extremely low gate leakage of similar to 10(-1)2 A/mm, and a desirable dielectric/semiconductor interface quality with interface state density in level of similar to 1012 cm(-2)eV(-1). Meanwhile, a maximum drain current of 600mA/mm has been achieved together with an on-state resistance (Ron) of 10.7 similar to center dot mm and a specific Ron of 2.62 m Omega center dot cm(2).