Correlation between OCVD carrier lifetime vs temperature measurements and reverse recovery behavior of the body diode of SiC power MOSFETs. (October 2020)

• Record Type: Journal Article
• Authors: Sapienza, S.; Sozzi, G.; Santoro, D.; Cova, P.; Delmonte, N.; Verrini, G.; Chiorboli, G.
• Is Part Of: Microelectronics and reliability. Volume 113(2020)
• Publication Date: 2020-10
• Subjects: Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2020.113937
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: The reverse recovery (RR) behavior of SiC MOSFET body diode is of great importance in power application, where these devices are used in a wide range of operating temperatures. The carrier lifetime in the drift region varies with temperature, and it heavily affects the tailoring of the RR current, opening reliability issues related to the RR voltage amplitude and to possible anomalous voltage oscillations during the recovery. From the users' point of view, it would be useful to have a simple technique able to give predictive information about the body diode RR behavior of commercial devices over the whole range of working temperatures. An experimental-simulation approach is presented in this paper to correlate the carrier lifetime measured by simple OCVD measurements versus temperature with the RR behavior of the body diode, that can be useful at the design stage of power converters. Simulations of the body diode reverse-recovery are performed for a wide range of carrier lifetimes. This allows to estimate the effect of changes of carrier lifetime with temperature on the body diode switching transients. Preliminary results obtained with a 1700 V/5A commercial MOSFET are shown. Highlights: The carrier lifetime measured by OCVD versus temperature is correlated with the reverse recovery of a SiC MOSFET body diode. The measured lifetime is found to increase following a power-law dependence on temperature with exponent of 1.5. A numerical model of a possible SiC body diode is realized with the Synopsys Sentaurus TCAD suite. The impact of carrier lifetime changes with temperature on the body diode switching behavior is evaluated by simulations. Simulations show a beneficial effect of the temperature increase on the diode softness for low minority carrier lifetimes. OCVD measurements can give indication about the temperature evolution of the switching behavior of MOSFET body diode. The presented experimental-simulation approach can be useful at the design stage of power converters.