Origin of the Flatband-Voltage Roll-Off Phenomenon in Metal/High-k Gate Stacks

被引:37
作者
Bersuker, Gennadi [1 ]
Park, Chang Seo [1 ]
Wen, Huang-Chun [1 ]
Choi, K. [1 ]
Price, Jimmy [1 ]
Lysaght, Patrick [1 ]
Tseng, Hsing-Huang [1 ]
Sharia, O. [3 ]
Demkov, Alex [3 ]
Ryan, Jason T. [2 ]
Lenahan, P. [2 ]
机构
[1] SEMATECH, Austin, TX 78741 USA
[2] Penn State Univ, University Pk, PA USA
[3] Univ Texas Austin, Austin, TX 78712 USA
基金
美国国家科学基金会;
关键词
Flatband voltage roll-off; high-k dielectrics; metal gate work function; INITIO MOLECULAR-DYNAMICS; TOTAL-ENERGY CALCULATIONS; PHASE-SEPARATION; WORK FUNCTION; INTERFACE; DEFECTS; TECHNOLOGY; TRANSITION; SILICON; LAYER;
D O I
10.1109/TED.2010.2051863
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
The effect of flatband-voltage reduction [ roll-off (R-O)], which limits fabrication options for obtaining the needed band-edge threshold voltage values in transistors with highly scaled metal/high-k dielectric gate stacks, is discussed. The proposed mechanism causing this R-O phenomenon is suggested to be associated with the generation of positively charged oxygen vacancies in the interfacial SiO2 layer next to the Si substrate. The vacancies in the interfacial layer are induced by oxygen outdiffusing into the overlying high-k dielectric. The model is consistent with the variety of observations of R-O dependence on the electrode and substrate type, high-k dielectric composition and thickness, temperature, etc. The model's predictions were experimentally verified.
引用
收藏
页码:2047 / 2056
页数:10
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