Investigation on Total-Ionizing-Dose Radiation Response for 700 V Double-RESURF SOI LDMOS

Total-ionizing-dose (TID) radiation response for 700 V double reduced surface field (RESURF) silicon-on-insulator (SOI) lateral double-diffused metal-oxide-silicon (LDMOS) is investigated in this article. Degradation mechanisms of breakdown voltage ( BV ), threshold voltage ( $V_{\mathrm {th}}$ ), linear drain current ( $I_{d\mathrm {lin}}$ ), and saturated drain current ( $I_{d\mathrm {sat}}$ ) are revealed by simulation. Multi-interface irradiation damage with oxide trapped charge generation is analyzed, which causes complex modulation on electric field distribution and carrier transport. BV degradation is ascribed to the original charge balance broken in bulk. The doping concentration of the P-top layer is equivalently reduced by oxide trapped charge in field oxide (FOX), and the doping concentration of the N-drift region is equivalently increased by oxide trapped charge in buried oxide. Consequently, the surface electric field at source side is enhanced, and a more uniform distribution is achieved, resulting in BV increased. $I_{d\mathrm {lin}}$ and $I_{d\mathrm {sat}}$ increasing are ascribed to ON-resistance reduced. The inversion layer in the P-top layer and the accumulation layer at the bottom of the N-drift region provide low resistance conduction paths. Compared to $I_{d\mathrm {sat}}$ , $I_{d\mathrm {lin}}$ shows insensitivity to oxide trapped charge in FOX layer because of the P-top layer shielding at a low drain voltage ( $V_{d}$ ).