1.1 ,This test method covers the use of the subthreshold charge separation technique for analysis of ionizing radiation degradation of a gate dielectric in a metal-oxide-semiconductor-field-effect transistor (MOSFET) and an isolation dielectric in a parasitic MOSFET.2^,3^,4 The subthreshold technique is used to separate the ionizing radiation-induced inversion voltage shift, Δ,V_INV into voltage shifts due to oxide trapped charge, Δ,V_ot and interface traps, Δ,V _it. This technique uses the pre- and post-irradiation drain to source current versus gate voltage characteristics in the MOSFET subthreshold region.