Total Ionizing Dose Effect and Single Event Burnout of VDMOS with Different Inter Layer Dielectric and Passivation

Abstract

In this paper, Total Ionizing Dose (TID) and Single Event Burnout (SEB) effects are investigated on self-developed power VDMOS devices with breakdown voltage (BV) of 200 V. Different inter layer dielectrics (ILD) including Borophosphosilicate glass (BPSG) and Si3N4, and different passivation layers including Si3N4 and SiO2 are tested to evaluate their radiation hardness. The TID results indicate that the threshold voltage VTH of VDMOS is negatively shifted after radiation, and can barely be recovered by post TID annealing. As an ILD layer, Si3N4 is proved to be better than BPSG with less VTH shift. Passivation layer can also influence the TID hardness, which increases with the layer thickness. Heavy ion radiation tests indicate that the devices with different ILD and passivation designs can barely influence the SEB effects. All tested devices with normal breakdown voltage of 200 V cannot survive at VDS more than 80 V under heavy ion radiation.