Normalization Indicator of Ion-Induced Radiation Damage in Power VDMOS Transistors

This work presents the impact of heavy ion irradiation on vertical-diffused metal-oxide-semiconductor field-effect transistors (VDMOSFETs), particularly focusing on the ionization and displacement damage pivotal for the operation of devices in space environments. We conducted experiments using irradiation with chlorine, silicon, fluorine, and oxygen ions. Our analysis involves calculating the linear energy transfer (LET) and nonionizing energy loss (NIEL) for various ion incidences, followed by determining the ionizing absorbed dose ( $D _{\mathrm {i}}$ ) and displacement absorbed dose ( $D _{\mathrm {d}}$ ) based on these parameters. Subsequently, we normalized the effects of heavy ion irradiation by examining the threshold voltage shift ( $\Delta V _{\mathrm {TH}}$ ) for ionization damage, and the drain-leakage current variation ( $\Delta I _{\mathrm {DLC}}$ ) and drain-saturation current variation ( $\Delta I _{\mathrm {DSC}}$ ) for displacement damage. Our findings reveal that the displacement damage, characterized by the $\Delta I _{\mathrm {DLC}}$ indicator, serves as a dependable metric for normalizing the impact across varying ion species. This discovery is significant for the equivalent study of different kinds of spaceborne charged ion irradiation in power VDMOS transistors.