Title :
Dual Metal Gates with Band-Edge Work Functions on Novel HfLaO High-K Gate Dielectric
Author :
Wang, X.P. ; Shen, C. ; Li, Ming-Fu ; Yu, H.Y. ; Sun, Yiyang ; Feng, Y.P. ; Lim, Andy ; Sik, Hwang Wan ; Chin, Albert ; Yeo, Y.C. ; Lo, Patrick ; Kwong, D.L.
Author_Institution :
Dept. of ECE, Singapore Nat. Univ.
Abstract :
In this work, by using a novel HfLaO high-kappa (HK) gate dielectric, we show for the first time that with a thermal budget of 1000 degC, Fermi-Pinning in the HK-metal gate (MG) stack can be released. The effective metal work function (EWF) can be tuned by a wide range more than the requirement of bulk CMOSFETs, and also fits the future UTB-SOI CMOSFETs when Si body thickness is approaching 3 nm or less. As prototype examples, TaN gate with EWF ~3.9-4.4 eV and TaN/Pt gate with EWF ~5.5 eV are shown. In addition, by replacing HfO2 with HfLaO, high k value and low gate tunneling are maintained, BTI Vth instability is improved by one order. These new findings are correlated to the enhanced thermal stability and significantly reduced oxygen vacancy density in HfLaO compared to HfO 2 as estimated by the first-principles calculations
Keywords :
Fermi level; MOSFET; ab initio calculations; dielectric materials; dielectric properties; hafnium compounds; high-k dielectric thin films; lanthanum compounds; leakage currents; tantalum compounds; thermal stability; work function; 1000 C; CMOSFET; Fermi-Pinning effect; HfLaO; HfO2; TaN-Pt; UTB-SOI; band-edge work functions; dual metal gates; high-k gate dielectric; oxygen vacancy density; thermal stability; Dielectrics; Hafnium compounds; Hafnium oxide; MOSFETs; Oxygen; Simulated annealing; Thermal stresses; Very large scale integration; Virtual colonoscopy; Voltage;
Conference_Titel :
VLSI Technology, 2006. Digest of Technical Papers. 2006 Symposium on
Conference_Location :
Honolulu, HI
Print_ISBN :
1-4244-0005-8
DOI :
10.1109/VLSIT.2006.1705191
