The Simulation Research Of Single-event Effect In Power UMOSFETs

Power MOSFETs are vulnerable to single-event effect (SEE) induced by energetic heavyions in space radiation environment. It mainly includes single-event burnout (SEB) andsingle-event rupture (SEGR). The occurrence of SEE can cause thermal destruction of thedevice. Power transistors are widely used in space and atmospheric applications these years,the research of radiation resistance and hardened device is needed. This paper gives thesimulation results of SEE in power UMOSFET (trench-gate MOSFET).The purpose of this paper is to simulate and analyze the SEE in standard powerUMOSFETs and then give the SEE hardening solutions. It is hoped that the other electricalparameters could remain unchanged as much as possible. The occurrence of SEB mainlydepends on the parasitic bipolar transistor in power UMOSFETs, so we improve the SEBperformance according to restraining the work of parasitic bipolar transistor. The research ofSEB gives the burnout threshold voltage and the simulation results of SEGR are alsocompared with SEB.Firstly, this paper gives the simulation results of the electrical properties and single-eventeffect in standard power UMOSFETs, and the influence to SEB when changing the carrierlifetime, emitter doping and p~+plug are given and analyzed. Then SEE hardened structuresare proposed. It includes p~+plug enlargement, adding a buffer layer and source schottkycontact. These hardening solutions can all improved the SEE performance effectively. For p~+plug enlargement and adding a buffer layer, the SEB and SEGR threshold voltage are bothsimulated, the structure can also improve the SEGR performance. Different gate bias andtemperatures are discussed in this part. For the structure with source schottky contact, wehave changed some parameters to optimize the operating current and threshold voltage aftersimulating the SEE, and then the optimized structure with a buffer layer is given. Thediscussion results can provide some reference to the design of radiation hardened device inthe future.