Mechanism and Improvement of On-Resistance Degradation Induced by Avalanche Breakdown in Lateral DMOS Transistors

On-resistance (R_on) degradation induced by avalanche breakdown is investigated in lateral double-diffused MOS transistors with different dosages of n-type drain drift (NDD) region. R_on degradation is caused by interface state and positive oxide-trapped charge created near the drain-side polygate edge. The device with a higher NDD dosage generates less interface state but more positive oxide-trapped charge, leading to a reduction in R_on degradation. Such a result reveals that increasing NDD dosage reduces avalanche-breakdown-induced R_on degradation.