Total-Ionizing-Dose Radiation-Induced Dual-Channel Leakage Current at Unclosed Edge Termination for High Voltage SOI LDMOS

Abstract

Total-ionizing-dose (TID) radiation response on unclosed edge termination is investigated for high voltage silicon-on-insulator (SOI) laterally diffused metal-oxide-semiconductor (LDMOS) in this article. Radiation-induced dual-channel leakage current model is proposed to reveal the mechanism of leakage current generation at OFF-state. Radiation causes a mass of positive oxide trapped charges generated in field oxide (FOX) layer and buried oxide layer. Owing to the P-SOI layer with significantly low doping concentration, two inversion channels are formed at the surface and bottom in the edge termination region, which provides parallel conduction paths. Electrons from the source N+ are pulled down and flow along the bottom channel while punchthrough occurring. The radiation-induced leakage current could be suppressed by thinning FOX layer, increasing the doping concentration of the P-SOI layer, and thickening the SOI layer.