Mechanism and improvement of on-resistance degradation induced by avalanche breakdown in lateral DMOS transistors

On-resistance ([R.sub.on]) degradation induced by avalanche breakdown is examined in lateral double-diffused MOS transistors with different dosages of n-type drain drift (NDD) region. The device with a high NDD dosage has generated less interface state but more positive oxide-trapped charge, revealing that NDD dosage has reduced avalanche-breakdown-induced [R.sub.on] degradation.