Study On Single-Event Burnout And Hardness Structure For The 4H-SiC UMOSFETs

In recent years,SiC materials have become a research hotspot in the power semiconductor industry.SiC power MOSFET devices have been widely used in the field of power semiconductor devices working in high voltage,high frequency,especially high temperature and high radiation environments.SiC power UMOSFET further improves the electrical characteristics on the basis of retaining the advantages of SiC power VDMOSFET,with excellent performance and bright application prospects.With the rapid development of China's aerospace industry,a large number of SiC power MOSFET devices need to work in the space radiation environment,and are facing the test of serious radiation effects such as Single event burnout effect(SEB).However,in the field of SEB research of SiC power MOSFETs,there is relatively little disclosure of SEB research results for SiC power UMOSFETs,and it faces the blockade of core technologies strengthened by foreign SEBs and the prohibition of related anti-radiation components.Based on this,this article studies the SEB effect of SiC power UMOSFET and related strengthening methods.The purpose is to design SiC power UMOSFET devices with excellent electrical performance and SEB resistance.First,this paper studies the trigger mechanism,sensitive area,trigger conditions,and related performance characteristics of the SiC power UMOSFET SEB effect,and studies the resistance of the traditional SEB reinforcement technology P+ source region expansion and N buffer layer in the effect of SEB reinforcement of SiC power UMOSFET.Subsequently,this paper studies the SEB effect of a new type of SEB-reinforced SiC power UMOSFET(NITG-MOSFET)structure with N island buffer layer and its related performance characterization.The N island buffer layer effectively reduces the the high electric field and impact ionization of SiC power UMOSFET drift/substrate junction improve the device's resistance to SEB,and the N island buffer layer will not affect the basic electrical characteristics of SiC power UMOSFET.At the same time,this paper also analyzes and discusses in detail the impact of the parameter changes of the N-island buffer layer on the resistance of the NITG-MOSFET to SEB reinforcement.It also describes in detail the process steps of the NITG-MOSFET structure and introduces the technical feasibility.Finally,this paper studies and explains the differences between the SiC power UMOSFET drainsource current and the global device temperature in characterizing the SEB effect after high-energy heavy ions are incident.At the same time,the SiC power UMOSFET structure with double N island buffer layer is studied in this paper.The double N island buffer layer suppresses and weakens the impact ionization inside the device caused by high-energy heavy ion incidence,and the load caused by impact ionization.The surge of electrons and the self-heating effect make the resistance of SiC power UMOSFET to SEB thermal damage greatly improved.