关键词: SGT, 总剂量效应, 阈值电压漂移, MOSFET

Abstract: Total ionizing dose radiation experiments with two different biases on 30 V SGT N-channel MOSFET are carried out. As the total dose of ⁶⁰Co γ source rays increases, the transfer curves and DC parameter variations of the devices before and after the experiments for the two biases are given. The trends and mechanisms of the changes of the SGT power devices with the dose and bias are revealed.The results of the study show that the threshold voltage, on-resistance and breakdown voltage of the device under both biases all decrease with the increase of the total ionizing dose.The difference is that the amplitude of the changes in the main parameters in the OFF state is narrowed, with relatively small decreases.At the same time, the phenomenon that the breakdown voltage firstly increases and then decreases occurs. The analysis suggests that under theaction of ⁶⁰Co γ source rays, the polysilicon shielding gate below the trench gate of the device has a relatively thick oxide layer, and the thick oxide layer at the cell and termination at the low dose produces a total dose effect, which makes the SGT power device undergo a change in the local field strength, resulting in this changes.

Key words: SGT, total ionizing dose, threshold voltage shift, MOSFET