Fig. 3: Emission microscopy of 4H-SiC power MOSFET under continuous gate switching.

a Background-corrected images of the reverse side of the 4H-SiC MOSFET chip using a 5-time magnification objective with an emission microscope. The first image is illuminated to present the chip structure whereas the other images show the photon emission upon gate switching between −10 V and 10 V with various frequencies. b An illuminated image and an image of the photon emission as shown in a, however with a 100-time magnification objective. c Background corrected cumulative photon count rate versus frequency.