Reseach Of Single-event Effect And Radiation Hardening For Power MOSFET

With the development of aerospace engineering,a lot of space instrumentations are required to apply in the radiation environments.Space radiation environment contains a variety of high-energy charged particles.High-energy charged particles can interact with electronic devices,which may lead to single event effects(SEE).Single event effects mainly include single event burnout(SEB)and single event gate rupture(SEGR),which could result in the burnout of power source in space instrumentations,and give a serious threat to the orbit lifetime of satellites and spacecrafts.Facing the current situations of foreign core technology blockade and radiation-hardened component embargo,the research of single event effects on power MOSFET and the development of high-performance and radiation-hardened power MOSFET devices are becoming serious problems.This paper mainly investigates the issues of single event effects and radiation hardening on power MOSFET.For the lack of current researchs on single event effects of Trench-UMOSFET,this paper studies the SEB and SEGR effects,which includes triggering mechanism,sensitive areas and performance characterization.Currently,conventional reinforcement technology improves the SEB performance of power MOSFET while reducing the basic electrical characteristics.Based on this problem,we propose two novel SEB hardening Trench-UMOSFET structures as SD-UMOSFET and ACCUFET,and give the research of SEB characteristics on FFR termination structure for the first time,in order to achieve the purpose of improving SEB performance without sacrificing the forward characteristic of the device.In order to improve the traditional carrier lifetime control method,this paper proposes the local carrier lifetime control method for SEB hardening.It proves that the method could reduce the leakage current density under the same SEB hardening effect.Based on the theoretical model and simulation data analysis of single event effect,the main contents are summarized as follows:First of all,we propose the study of SEB and SEGR effects on a novel Trench-UMOSFET(SGE-UMOSFET).We show the most sensitive horizontal incident position to trigger a SEB or SEGR,and the most sensitive region to trigger a SEB or SEGR in the device structure.We also find the easiest and most effective way to trigger a SEB or SEGR.Compared with the common Trench-UMOSFET,SGE-UMOSFET presents a more resistant ability to single event effects.Compared with the traditional VDMOSFET,the Trench-UMOSFET could have smaller latch current density under the same bias condition.As the parasitic BJT is more difficult to trigger,it has much better SEB hardening performance;In order to ensure the SEGR performance of trench gate UMOSFET,it requires a higher gate oxide dielectric quality at the same time.Secondly,we propose two novel Trench-UMOSFET structures as SD-UMOSFET and ACCUFET.The research gives the most sensitive horizontal incident position to trigger a SEB and the SEB hardening mechanism for the two novel structures,and obtain the method to realize the optimal concentration of buffer layer.Compard with the extended P+ active region SEB hardening UMOSFET structure,the proposed structures could improve the SEB performance without affecting the forward saturation current.The research shows that,the optimized SD-UMOSFET and ACCUFET structures with n buffer layer can be immune to SEB throughout entire operating voltage range.Once more,we propose the research on SEB characteristics of FFR termination structure.We discusse the most sensitive horizontal incident positions,and give the SEB triggering point and SEB triggering mechanism for the structure.The SEB hardening mechanism for buffer layer of termination is presented,and the SEB performance of the hardened FFR termination is characterized.It is proved that the SOA gradually reaches saturation with the increase of buffer layer thickness.The SOA value of the optimized hardening structure with buffer layer in this paper could reach more than 90.0%of the breakdown voltage.Finally,we propose the local carrier lifetime control method.The local carrier lifetime control region and SEB hardening mechanism are studied,and the SEB performance with different carrier lifetime control is characterized.Compared with the traditional carrier lifetime control method,the proposed method has a lower leakage current density under the same SEB hardening effect.Moreover,compared with the buffer layer technology,the method can avoid a significant increase in on-resistance and has no influence on the forward operating characteristic.