Observation of current filaments in IGBTs with thermoreflectance microscopy

Al modification as indicator of current filaments in IGBTs under repetitive SC operation

“…12 displays the repetitive SC measurement result for a V CE of 400 V and V GE of 23 V. The results are compared for both L par with TRM measurements. In this case, uniform Al reconstruction was found after 20,000 repetitive SC pulses for both L par and similar result after several thousands of SC pulses under TRM microscope [2]. The homogeneous distribution is due to the fact that current density has reduced inside the filament region due to the lower SC current density at lower applied gate voltage.…”

“…Scale: (x: 3.7 mm, y: 2.8 mm). The dark black line on the chip is the bond wire [2,3] Fig. 8 Observed temperature distribution using TRM for 400, 500 and 600 V with reference to Fig.…”

“…International Symposium on Power Semiconductor Devices & ICs (ISPSD 2018) [2,3]. One of the important parameters under SC stress is the parasitic inductance (L par ).…”

“…Many authors have investigated the SC-SOA for different voltage classes ranging from 1200 to 6500 V [1][2][3][4][5][6][7][8][9]. A hypothesis was developed for device destruction based on simulation results, explaining the avalanche generation rate exceeding the critical value near n-base/n-field-stop junction [6][7][8].…”

“…Further investigations were carried out experimentally to observe the current filaments in the IGBTs using thermo‐reflectance microscopy (TRM) [10] under repetitive SC operation. The results published in [2] uncover a large non‐destructive current‐filament range. In this work, repetitive SC measurements were performed on 15 A–1200 V class IGBTs using an open chip soldered on direct copper bonded substrate.…”