Characterization of positive bias temperature instability of NMOSFET with high-k/metal gate last process  

作　　者：任尚清 杨红 唐波 徐昊 罗维春 唐兆云 徐烨锋 许静 王大海 李俊峰 闫江 赵超 陈大鹏 叶甜春 王文武 

机构地区：[1]Key Laboratory of Microelectronics Devices and Integrated Technology, Institute of Microelectronics,Chinese Academy of Sciences

出　　处：《Journal of Semiconductors》2015年第1期86-89,共4页半导体学报（英文版）

基　　金：Project supported by the Important National Science&Technology Specific Projects(No.2009ZX02035);the National Natural Science Foundation of China(Nos.61176091,61306129)

摘　　要：Positive bias temperature instability（PBTI） characteristics and degradation mechanisms of NMOSFET with high-k/metal gate last process have been systematically investigated. The time evolution of threshold voltage shift during PBTI stress still follows a power law. However, the exponent n decreases from 0.26 to 0.16 linearly as the gate stress voltage increases from 0.6 to 1.2 V. There is no interface state generation during stress because of the negligible sub-threshold swing change. Moreover, the activation energy is 0.1 e V, which implies that electrons directly tunnel into high-k bulk and are trapped by pre-existing traps resulting into PBTI degradation. During recovery the threshold voltage shift is linear in lgt, and a mathematical model is proposed to express threshold voltage shift.Positive bias temperature instability（PBTI） characteristics and degradation mechanisms of NMOSFET with high-k/metal gate last process have been systematically investigated. The time evolution of threshold voltage shift during PBTI stress still follows a power law. However, the exponent n decreases from 0.26 to 0.16 linearly as the gate stress voltage increases from 0.6 to 1.2 V. There is no interface state generation during stress because of the negligible sub-threshold swing change. Moreover, the activation energy is 0.1 e V, which implies that electrons directly tunnel into high-k bulk and are trapped by pre-existing traps resulting into PBTI degradation. During recovery the threshold voltage shift is linear in lgt, and a mathematical model is proposed to express threshold voltage shift.

关 键 词：positive bias temperature instability（PBTI） high-k metal gate 

分 类 号：TN386[电子电信—物理电子学]