The impact of heavy ion irradiation on the performance of novel REDI LDMOS power devices

摘要

In this paper, the impact of heavy ion irradiation on the performance of novel REDI LDMOS (RESURF Dielectric Inserted Lateral Double-diffused MOS transistor) power devices is experimentally investigated for the first time. The performance degradation of REDI LDMOS caused by micro-dose effect and displacement damage (DD) is demonstrated, and the impact of ion fluence and device geometry is analysed. Different degradation behavior occur due to the intrinsic random incident of heavy ions. The threshold voltage (V-th) of the device is barely changed after irradiation. The off-state leakage current (I-off) of the device may increase or decrease after irradiation, which can change by up to 2 orders of magnitude. The breakdown voltage (BV) of REDI LDMOS may decrease by up to 50%. In addition, the on-resistance (R-on) and on-state current (I-on) of the device are changed by up to about 40%. Further, heavy ion fluence has significant effect on device characteristics after irradiation. For low-fluence (5 x 10(8) ions cm(-2)), the degradation of BV is the main problem caused by irradiation. And BV, R-on and I-on degradation should be paid attention for devices irradiated by high-fluence (5 x 10(9) ions cm(-2)) heavy ion. Besides, the distance between p(+) region and the drift region boundary (L-D) has negligible effect on the performance degradation of the irradiated device. However, the maximum value and variation of BV degradation of devices irradiated by high-fluence heavy ion increase with the increase of the length of the gate overlap the drift region (L-ov). The results are of great significance for the research of the radiation-hardened technology of power devices.