Simulation And Experimental Analysis For Radiation Effect Of Super Junction MOSFET

Super junction MOSFET inherited advantages of VDMOS such as high input impedance,low drive current,fast switching speed,good thermal stability,wide area of safe operation,etc.On the base of it,the contradiction between the breakdown voltage and on resistance is greatly alleviated by super junction MOSFET.And with the rapid development of aerospace technology and nuclear technology,more and more power electronic devices are applied in various radiation environments.The radiation has degraded the performance of power electronic devices and then greatly reduced the reliability and longevity of power devices.At present,power VDMOS are widely used in satellite and other equipment.As a kind of power electronics device which has a great improvement of electrical properties than traditional VDMOS,Super junction MOSFET will replace the high-pressure VDMOS in aerospace field.So the researches for the radiation mechanism of super junction MOSFET and its radiation hardening technologies are very important.In this thesis,the basic theory of radiation damage is discussed.Then the total dose radiation effect and single event radiation effect of super junction MOSFET are proposed:1.The radiation damage mechanism of total dose radiation and radiation hardening measures of super junction MOSFET are studied.Simulation and experimental researches shows that:the total dose radiation has great influence on the threshold voltage of the cell,while has no influence on the breakdown voltage and the conductivity resistance of the cell.And when the radiation dose is relatively small,the breakdown voltage of terminal changes less.But the breakdown voltage of terminal decreases obviously when the radiation dose increases gradually.According to the theoretical analysis,the damage mechanism of total dose radiation is mainly to introduce the fixed charge and interface state in the oxide layer and then affected the electrical characteristics of the device.Since the fixed charges and interface states are introduced in field oxide after the total dose radiation,the charge balance of terminal is broken and then the breakdown voltage of breakdown voltage is lower.The fixed positive charges are introduced in the gate oxide after the total dose radiation simultaneously.Hence the threshold voltage of super junction MOSFET is lower as well.Based on above research,several measures of total dose radiation hardening are proposed.2.The radiation damage mechanism of single event radiation and radiation hardening measures of super junction MOSFET are studied.The damage mechanism of single event radiation is mainly caused by the electron hole induced by single event incident,which causes the device to burn down.The radiation resistances of super junction MOSFET for different incident positions are studied by simulation.Based on above research,several measures of single event radiation hardening are proposed.The total dose radiation and single event radiation for super junction MOSFET are studied theoretically in this article.The radiation damage mechanisms are clear and verified by simulation and experimental researches.On the basis of this,the reinforcement measures are put forward.The radiation theory guidance and the direction of reinforcement are provided for future researchers in this paper.Hence this paper has the vital significance foe the super junction MOSFET radiation resistance reinforcement.