Improved Model on Buried-Oxide Damage Induced by Total-Ionizing-Dose Effect for HV SOI LDMOS

In this article, an improved model on buried-oxide (BOX) damage induced by total-ionizing-dose (TID) effect considering positive oxide trapped charge ( ${N}_{\text {ot}}$ ) generated in silicon on insulator (SOI) /BOX interface under negative electric field bias (field lines perpendicular to the SOI/BOX interface pointing from the top to the bottom of the BOX) and ${N}_{\text {ot}}$ saturation effect is proposed and adopted in accurate simulated analysis to predict the postirradiation device behavior. Moreover, the mechanism of high-voltage (HV) SOI lateral double diffused metal oxide semiconductor field effect transistor (LDMOS) degradation during irradiation is also revealed by the proposed accurate simulation method. Tolerance design for radiation-hardened HV SOI LDMOS is discussed with the aid of the presented model. The tradeoff between postirradiation electrical characteristics and fresh electrical characteristics should be taken into account to meet the radiation hardening requirement. The radiation-hardened-by-design LDMOS introduced in this article keeps an OFF-state breakdown voltage above 120 V at ${D} = {500}$ krad(Si) with operating voltage equal to 80 V, which is fabricated on a commercial SOI substrate material with plain interface quality parameters. The corresponding hardening strategy is also given.