恒压应力下超薄栅nMOSFET软击穿后的衬底电流特性  

Substrate Current Characteristics After Soft Breakdown in Ultra-Thin Gate Oxide nMOSFETs Under Constant Voltage Stress

作　　者：王彦刚[1] 许铭真[1] 谭长华[1] 段小蓉[1] 

机构地区：[1]北京大学微电子学研究所,北京100871

出　　处：《Journal of Semiconductors》2005年第5期999-1004,共6页半导体学报（英文版）

基　　金：国家重点基础研究专项经费资助项目(批准号:TG2000 036503)~~

摘　　要：研究了在恒压应力下超薄栅nMOSFET软击穿后的衬底电流特性.软击穿时间由衬底电流随时间的弛豫特性和器件输出特性测量时监测的衬底电流突变确定.发现软击穿时间的威布尔斜率和衬底特征击穿电流随温度的升高而增大.用类渗流模型模拟了软击穿后衬底电流与栅电压的关系.利用变频光泵效应讨论了超薄栅MOSFET低电压应力下衬底电流的来源,并解释了软击穿后衬底电流和栅电流之间的线性关系.The characteristics of the substrate current (I sub ) after soft breakdown (SBD) in ultra-thin gate oxide nMOSFETs are studied under constant voltage stress.The time to soft breakdown (t BD ) is obtained by the relaxation characteristics of the I sub with time and by monitoring the breaks of the I sub when measuring the output characteristics.It is found that both the Weibull slopes of t BD and the characteristic ΔI sub(SBD) (63% ΔI sub(SBD) ) increase with increasing test temperature.Furthermore,a percolation like conduction model is proposed to simulate the characteristics of the I sub versus the gate voltage after SBDs.The origin of the I sub and the linear relation between I sub and I g after SBD are discussed by the variable frequency light pumping effect.

关 键 词：衬底电流 软击穿 超薄栅氧化层 威布尔分布 变频光泵效应 

分 类 号：TN386[电子电信—物理电子学]