Normally-Off p-Channel AlGaN/GaN/AlGaN MESFET With High Breakdown Voltage and Ultra-Low Interface State Density
Huake Su, Tao Zhang, Shengrui Xu, Hongchang Tao, Jincheng Zhang, Yue Hao
Abstract
In this work, a novel normally-off p-channel AlGaN/GaN/AlGaN Metal-Semiconductor field effect transistor (MESFET) with threshold voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text {TH}}$ </tex-math></inline-formula> ) of −0.7 V is demonstrated. The state-of-the-art breakdown voltage of −198 V and breakdown electric field of 1 MV/cm are obtained for the fabricated MESFET with gate to drain distance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2~\mu \text{m}$ </tex-math></inline-formula> , owing to the high bandgap p-AlGaN layer. Moreover, the high-quality Schottky interface with ultra-low interface state density of 1.4- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.4\times 10^{{11}}$ </tex-math></inline-formula> cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-2} \cdot $ </tex-math></inline-formula> eV−1, which is extracted by conductance method, contributes to the negligible hysteresis effect of the ten-consecutive dual-swept I-V curves. The novel AlGaN/GaN/AlGaN p-MESFETs with high breakdown electric field and stable I-V characteristics show a great potential for next-generation GaN integrated circuit.