Accurate SiC MOSFET Chip V_gs Extraction Based on Parasitic Parameter Impact Compensation

With the growing use of SiC MOSFET in power electronic equipment, it is meaningful to extract precise typical waveforms and characteristics for device manufacture, converter design, and operating evaluation. Many solutions have been proposed to improve measurement precision by equipment and essential techniques. However, the measured object should also be accurately identified as the existing measurement result consisting of the expected gate-source voltage (v(GS)) and voltage drops on parasitic parameters between measuring points. This article, first, reveals the v(GS) measurement deviation of TO-247-4 and TO-247-3 devices during the switching process and crosstalk, based on the equivalent circuit model and simulation waveforms. According to the clarification of the measured object, an improved v(GS) extraction method is proposed to eliminate this deviation. Voltage drops on parasitic parameters are compensated, with the help of high-precision equipment and the proven parasitic parameter extraction technique. Experiments are constructed to verify the analysis of measurement deviation and the availability of the proposed method. Comparison between various operating conditions emphasizes its necessity, especially in high-capacity and low-driving-resistor applications, contributing to characterization, operating condition monitoring, protection design, and measurement understanding of wide band-gap devices.