An Enhanced Characterization Method of SiC MOSFETs in the High-Voltage Saturation Region With Reduced Self-Heating

Accurate device modeling, short-circuit (SC) prediction, and protection for SiC MOSFETs require accurate measurement of their saturation characteristics under high drain-source voltages. However, conventional curve tracers are limited by power constraints, parasitic elements, and especially the device's intrinsic turn-on time, which together constrain <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$di/dt$</tex-math></inline-formula>. This makes it difficult to characterize behavior in high-voltage, high-current regions, since the long duration required to reach steady state can cause significant self-heating, reducing accuracy or even damaging the device. This letter proposes a test topology using multiple parallel devices as auxiliary switches to control the measurement and accelerate the turn-on transient while keeping the device under test normally on. To accurately measure the internal gate voltage during an ultra-narrow pulse, we propose a high-impedance gate drive circuit, eliminating the influence of the voltage drop across the device's intrinsic gate resistance. The measured results capture the full range of transfer and output characteristics of the SiC MOSFET and show good agreement with curve tracer data in the low-voltage region. At <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_{\text{ds}} = 20 \,\mathrm{V}$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_{\text{gs}} = 20 \,\mathrm{V}$</tex-math></inline-formula> under room temperature, the proposed method limits the temperature rise to within <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$4 \,{{\mathrm{^{\circ }}{\mathrm{C}}}}$</tex-math></inline-formula>, compared to nearly <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$100 \,{{{^{\circ }}{\mathrm{C}}}}$</tex-math></inline-formula> with a power device analyzer, thereby enabling more accurate device characterization and modeling.