Time resolved emission observation from top surface in avalanche breakdown of power MOSFET

Time resolved emission (TRE) microscopy can detect photons, and its signal-to-noise (S/N) ratio is higher than that of Photo Emission Microscopy under weak emission conditions. This is the first study to show the TRE observation in avalanche breakdown through thick source metal from the top surface of power MOSFET. TRE is an effective method to detect several photons, however, the strong emission range saturate the output of TRE detectors and this phenomenon disturbs accurate photon measurement. Our study results show that the photon count behavior is consistent with the oscillation of avalanche current. Also, the distribution of photon count density in the regions of the device is different, which indicates that there is distribution of current density in MOSFET. The described approach has the capacity to observe the current density distribution without any power device electrode metal removal and can be applied to measure the oscillation behavior of avalanche current.