Numerical and Experimental Investigation of TID Radiation Effects on the Breakdown Voltage of 400-V SOI NLDMOSFETs

The breakdown voltage (BVDS) variation of 400-V silicon-on-insulator (SOI) n-channel laterally diffused metal-oxide-semiconductor field-effect transistors (NLDMOSFETs) is examined after exposure to a total ionizing dose (TID). The results for OFF bias and ON bias are explored.For the OFF bias, BVDS increases first and then degrades with accumulated dose. For the ON bias, the irradiated device shows soft breakdown after irradiation. The physical mechanisms for these variations are analyzed and confirmed by technology computer-aided design (TCAD) simulation.