漂移区长度对LDMOSFET总电离剂量效应的影响

Abstract The adjustment of drift region length increases the design flexibility of laterally diffused metal oxide semiconductor field effect transistor (LDMOSFET) characteristics, such as breakdown voltage and on-resistance. However, its impact on the total ionizing dose (TID) effects on the device cannot be ignored. The changes in threshold voltage ( V th ), transconductance ( g m ), drain current ( I d ), and on-resistance ( R on ) of N-channel LDMOSFET (NLDMOSFET) with two different drift region lengths after TID irradiation were studied in this article. We found that the shift of V th and g m after irradiation was almost identical for both devices, whereas there was a noticeable difference in the shift of I d and R on . The influences of traps and interface states in gate oxide and field oxide on device characteristics were discussed through technology computer-aided design (TCAD). Ultimately, we discovered that the degradation of V th after irradiation was primarily related to the gate oxide, while the degradation of drain current in linear region ( I dlin ) after irradiation was mainly related to the drift region. The degradation of g m and R on were related to the degradation of V th and I d . Although the long drift region is beneficial to the breakdown and power characteristics of LDMOS devices, it causes a significant deterioration in the TID effect, which is worth considering in the design of devices and circuits applied in radiation environment.