Research On The Radiation Effects Of VDMOS Power Devices In Space Instruments

Space radiation environment has a very important impact on human space activities.High-energy particles,cosmic rays and other factors in spacecraft working environment can trigger various radiation effects of typical devices and circuit systems in space instruments,such as TID,SEE,and SPDD.These radiation effects can result in data anomalies,functional interruptions,lifetime reductions and other consequences,and form a great resistance to the human exploration of space.Radiation effects of VDMOS devices are studied in this paper,and both simulative and experimental work is carried out.The main researches are as follows:(1)The structure,working principle and experimental scheme of VDMOS power devices are studied.The radiation effect mechanism of them are analyzed.Based on this,the experimental scheme of the radiation effect of VDMOS power devices is designed.(2)Simulation of radiation effect mechanism of VDMOS devices is carried out using semiconductor radiation simulation software.According to the mechanism of the main radiation effects of VDMOS devices,the radiation effects simulation model of the device is established.And the key electrical parameters of the device model are solved.And then the TID,SEE and the effect of cumulative dose on the sensitivity of SEE in VDMOS devices are studied,and the mechanism of the radiation effects are analyzed.(3)The experimental study on the radiation effects of VDMOS devices is carried out,and the experimental results and simulation results are analyzed synthetically.The radiation effects and the effects criterion of VDMOS devices are analyzed.Based on the designed experimental circuit and experimental scheme,the SEE,TID and the effect of cumulative dose on the sensitivity of SEE in VDMOS devices were analyzed by using the pulsed laser radiation source and the cobalt-60γ radiation source.And the mechanism of the experiments is analyzed.In this paper,the radiation effects of VDMOS devices are studied in combination with two methods of simulation and experiment.The experimental results show that the threshold voltage of VDMOS devices decreases with the increase of accumulated dose of ionizing radiation.The SEB voltage of the device increases with the dose increasing.The safe operating voltage of experimental devices is about 37.6% of the breakdown voltage when laser energy is 14 nJ.And the safe operating voltage decreases as the gate negative bias voltage increases,but it changes little as accumulated dose increases.This paper provides support for the study of the effect mechanism,anti-radiation design and aerospace applications of the device,and promotes space applications of COTS devices.The study makes contributions to our country’s aerospace industry.