Measurements for Superjunction MOSFETs: Limitations and Opportunities

• Published in: IEEE transactions on electron devices Vol. 66; no. 1; pp. 578 - 584
• Main Authors: Zulauf, Grayson D., Roig-Guitart, Jaume, Plummer, James D., Rivas-Davila, Juan M.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anomalies; Capacitance; Capacitance measurement; Capacitance-voltage characteristics; Depletion; Frequency measurement; Frequency shift; Hysteresis; Internal energy; MOSFETs; output capacitance (<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">C OSS); Perturbation methods; Power converters; Power measurement; power MOSFETs; Semiconductor device measurement; superjunction
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2018.2880952

Small-signal measurements of output capacitance (<inline-formula> <tex-math notation="LaTeX">{C_{\textsf {OSS}}} </tex-math></inline-formula>) are ubiquitous in power semiconductor datasheets and determine critical features of power converters. For silicon superjunction power MOSFETs (SJs), we report <inline-formula> <tex-math notation="LaTeX">{C_{\textsf {OSS}}} </tex-math></inline-formula> measurements with two key anomalies: variation with ac perturbation frequency and hysteresis with dc sweep direction. Using mixed-mode simulations, we attribute the frequency shift to the fundamental SJ structure and find that dc hysteresis is caused by charge trapping from uneven depletion fronts. We show that <inline-formula> <tex-math notation="LaTeX">{C_{\textsf {OSS}}} </tex-math></inline-formula> measurements on SJs do not accurately characterize large-signal operation, underestimating stored energy by up to four times and giving no indication of <inline-formula> <tex-math notation="LaTeX">{C_{\textsf {OSS}}} </tex-math></inline-formula> losses.