Dynamic RON and QOSS in P-GaN Power HEMTs Explained with the Hole Redistribution Model

There is a broad consensus in the literature about the critical role of Carbon (C) doping in determining dynamic <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RO N</tex> and current collapse in GaN power HEMTs. The physical mechanism is the emission, redistribution, and retrapping of holes within the carbon-doped buffer (“hole redistribution” in short) that affects the 2-DEG concentration with relatively long time constants, owing to the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.9-eV</tex> energy difference between the trap level and GaN valence band. Relatively less investigated is the role of C-traps on dynamic Qoss, that critically impacts switching losses. Here, we show by means of TCAD simulations that C-related traps are at the origin of both dynamic <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RON</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">QOSS</tex>.