High-<inline-formula> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> 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 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 ~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 (Ron) of 10.7 Ω·mm and a specific Ron of 2.62 mΩ·cm2.

Keywords

• k HfO₂%22%2C%22default_operator%22%3A%22AND%22%7D%7D%7D"> High <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">k</italic> HfO₂
• Y₂O₃ interfacial layer
• AlGaN/GaN MIS-HEMT
• gate controllability
• interface quality