超深亚微米PMOS器件的NBTI退化机理

对超深亚微米PMOS器件的负栅压温度不稳定性(NBTI)退化机理进行了研究.主要集中在对器件施加NBT和随后的PBT应力后器件阈值电压的漂移上.实验证明反型沟道中空穴在栅氧中的俘获以及氢分子在栅氧中的扩散是引起NBTI退化的主要原因.当应力条件变为PBT时，陷落的空穴可以快速退陷，但只有部分氢分子可以扩散回栅氧与衬底界面钝化硅悬挂键，这就导致了PBT条件下阈值电压只能部分恢复. 关键词： 超深亚微米PMOS器件 负偏压温度不稳定性 界面陷阱 氢气

Mechanism of NBTI degradation in ultra deep submicron PMOSFET's

The mechanism of negative bias temperature instability (NBTI) degradation in ultra deep submicron PMOSFET's is investigated. We mainly focus on the threshold voltage shift under subsequent positive bias temperature (PBT) stress after the preceding NBT. It's experimentally demonstrated that trapped holes from inversion channel and the diffusion of hydrogen molecules in the gate oxide are the major causes of NBTI degradation in PMOSFET's. When the condition is switched to PBT stress the trapped holes can be rapidly detrapped, but only a part of hydrogen molecules can diffuse back to the interface of gate oxide and substrate and repassivate silicon dangling bond, this is responsible for the threshold voltage being only partially recovered during PBT annealing.