on-Resistance Degradation Induced by Hot-Carrier Injection in SOI SJ-LDMOS

In this brief, anomalous hot-carrier degradation phenomenon in n-type superjunction lateral DMOS transistors on a SOI substrate is investigated. An unexpected on-resistance (R_on) decrease was observed at the beginning of stress, but R_on increases with the stress time. The reason was analyzed with the 3-D simulation of electrical field and impact ionization generation. The injection of hot holes into the field oxide near the drain region leads to the R_on decrease during the early stress period. With the increase of stress time, trapped hot holes accumulated in the field oxide and act as electron defects to trap electrons, altogether with hot electrons trapped in gate oxide above the accumulation region, contributing to R_on increase.