Accurate Measurement of Dynamic ON-Resistance in GaN Transistors at Steady-State

Abstract

Accurate characterization of the dynamic <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> -resistance (R <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${}_\textsc{on}$</tex-math></inline-formula> ) degradation is important to predict conduction losses for gallium nitride (GaN) high-electron-mobility transistors. However, even for the same device, many inconsistent results of dynamic R <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${}_\textsc{on}$</tex-math></inline-formula> based on pulsed measurements are reported in the literature. This letter reveals that insufficient test time leads to spurious dynamic R <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${}_\textsc{on}$</tex-math></inline-formula> results and even contradictory conclusions. We show that the time required for the dynamic R <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${}_\textsc{on}$</tex-math></inline-formula> to stabilize can be very long (∼ 3 min) for some commercial GaN devices and pulsed measurements fail to give accurate results. These findings are enabled by our proposed steady-state method using a hard-switching half-bridge with an active measurement circuit. It minimizes the influence of temperature on the R <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${}_\textsc{on}$</tex-math></inline-formula> , enabling to capture trap-related effects independently from the operation conditions. This letter raises awareness of the effect of poorly measured dynamic R <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${}_\textsc{on}$</tex-math></inline-formula> and highlights that steady-state methods should be applied for accurate measurements to predict their performance in real power converter operations.