N型LDMOS器件在关态雪崩击穿条件下的退化  

Off-state avalanche breakdown induced degradation in NLDMOS devices

作　　者：郭维[1] 丁扣宝[1] 韩成功[1] 朱大中[1] 韩雁[1] 

机构地区：[1]浙江大学信息与电子工程学系,浙江杭州310027

出　　处：《浙江大学学报（工学版）》2011年第6期1038-1042,共5页Journal of Zhejiang University：Engineering Science

基　　金：浙江省科学技术厅科技计划资助项目(2006C11007)

摘　　要：针对功率开关管在未箝位电感性开关转换时会反复发生雪崩击穿,引起器件参数退化的问题,对一种20V N型横向双扩散MOS器件(NLDMOS)在关态雪崩击穿条件下导通电阻的退化进行研究.通过恒定电流脉冲应力测试、TCAD(technology computer-aided design)仿真和电荷泵测试,分析研究导通电阻退化发生的区域及退化的微观机理,并针对实验结果提出2种退化机制:(1)NLDMOS漂移区中的空穴注入效应,这种机制会在器件表面产生镜像负电荷,造成开态导通电阻Ron的减少;(2)漂移区中的表面态增加效应,这种机制会造成载流子迁移率的下降,引起Ron的增加.这2种机制都随着雪崩击穿电流的增加而增强.Degradation behaviors of 20 V NLDMOS operated under off-state avalanche breakdown condition were presented to study the reliability issue caused by repeatedly avalanche breakdown of the N-type lateral double diffusion MOS transistor（NLDMOS）under unclamped inductive switching.The on-resistance degradation region and micro-mechanism were investigated by the analysis of constant current pulse stress tests,technology computer-aided design（TCAD） simulation and charge pumping measurements.Two different degradation mechanisms are identified：（1） The positive oxide-trapped charge accumulation effect in the N-type drift region induces the mirrored negative charges in the device surface,so the on-resistance decreases;（2）The surface states formation effect reduces the channel electron mobility,so the on-resistance increases.The both mechanisms are enhanced with the increasing avalanche breakdown current.

关 键 词：横向双扩散N型MOS器件 雪崩击穿 导通电阻退化 电荷泵 

分 类 号：TN40[电子电信—微电子学与固体电子学]