Study on the damage of power devices caused by parallel sealing of power transistors

DC potential barrier testing and infrared thermal imaging analysis were conducted on a GaN power transistor that experienced electrical failure due to parallel seam welding. The failure mechanism was revealed through full-wave simulation analysis. The results indicated that during the parallel seam welding process, a potential difference between the source and gate led to a significant induced current passing through the source-gate, causing gate breakdown and subsequent electrical failure. Based on the failure analysis and mechanism simulation, this paper proposes a method of equalizing the gate-source potential before seam welding. This approach effectively suppresses the softening of the gate barrier in the GaN die caused by the seam welding pulse current, significantly improving product reliability.