标题：TDDB characteristic and breakdown mechanism of ultra-thin SiO 2/HfO2 bilayer gate dielectrics
作者：Tao, Fenfen ;Yang, Hong ;Tang, Bo ;Tang, Zhaoyun ;Xu, Yefeng ;Xu, Jing ;Wang, Qingpu ;Yan, Jiang
作者机构：[Tao, Fenfen ;Wang, Qingpu ] School of Physics, Shandong University, Jinan 250100, China;[Tao, Fenfen ;Yang, Hong ;Tang, Bo ;Tang, Zhaoyun ;Xu, Yefeng 更多
来源：Journal of Semiconductors
摘要：The characteristics of TDDB (time-dependent dielectric breakdown) and SILC (stress-induced leakage current) for an ultra-thin SiO2/HfO 2 gate dielectric stack are studied. The EOT (equivalent-oxide- thickness) of the gate stack (Si/SiO2/HfO2/TiN/TiAl/TiN/W) is 0.91 nm. The field acceleration factor extracted in TDDB experiments is 1.59 s·cm/MV, and the maximum voltage is 1.06 V when the devices operate at 125°C for ten years. A detailed study on the defect generation mechanism induced by SILC is presented to deeply understand the breakdown behavior. The trap energy levels can be calculated by the SILC peaks: one SILC peak is most likely to be caused by the neutral oxygen vacancy in the HfO2 bulk layer at 0.51 eV below the Si conduction band minimum; another SILC peak is induced by the interface traps, which are aligned with the silicon conduction band edge. Furthermore, the great difference between the two SILC peaks demonstrates that the degeneration of the high-k layer dominates the breakdown behavior of the extremely thin gate dielectric. © 2014 Chinese Institute of Electronics.