Impact of $V_\mathsf {th}$ Instability of Schottky-Type p-GaN Gate HEMTs on Switching Behaviors
Xuyang Lu, Arnaud Videt, Soroush Faramehr, Ke Li, Vlad Marsic, Petar Igić, Nadir Idir
Abstract
Schottky-type p-GaN gate Gallium Nitride High Electron Mobility Transistors (GaN-HEMTs) suffer from 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">${V_{\mathsf {th}}}$</tex-math></inline-formula> ) instability phenomenon. Both positive and negative <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${V_{\mathsf {th}}}$</tex-math></inline-formula> shifts are reported when device undertakes the voltage bias, but the impact of this <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${V_{\mathsf {th}}}$</tex-math></inline-formula> instability phenomenon on device switching behaviors is less investigated. In this study, the drain-source voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${V_{\mathsf {ds}}}$</tex-math></inline-formula> ) induced bidirectional <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${V_{\mathsf {th}}}$</tex-math></inline-formula> shift in hard-switching condition is characterized and decoupled by an H-bridge based double-pulse test (DPT). Subsequently, the influence of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${V_{\mathsf {th}}}$</tex-math></inline-formula> shift on switching behaviors is theoretically analyzed and demonstrated through SPICE simulation and experiment, showing how a positive shifted <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${V_{\mathsf {th}}}$</tex-math></inline-formula> can reduce the device turn-on commutation speed and increase the switching losses, and vice versa. The results suggest that the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${V_{\mathsf {th}}}$</tex-math></inline-formula> instability phenomenon should be considered in accurate switching modeling.