Title :
Widely Tunable Work Function TaN/Ru Stacking Layer on HfLaO Gate Dielectric
Author :
Wang, X.P. ; Li, M.-F. ; Yu, H.Y. ; Yang, J.J. ; Chen, J.D. ; Zhu, C.X. ; Du, A.Y. ; Loh, W.-Y. ; Biesemans, S. ; Chin, Albert ; Lo, G.Q. ; Kwong, D.L.
Author_Institution :
Nat. Univ. of Singapore, Singapore
Abstract :
For the first time, we demonstrate experimentally that using HfLaO high-kappa gate dielectric and vertical stacks of TaN/Ru metal layers, dual metal gates with continuously tunable work function over a very wide range from 3.9 to 5.2 eV, can be achieved after 1000 degC annealing required by a conventional CMOS source/drain activation process. The wide tunability of work function for this bilayer metal structure is attributed to metal interdiffusion during annealing and the release of Fermi level pinning between metal gates (Ru and TaN) and HfLaO. Moreover, this change is thermally stable and unaffected by a subsequent high temperature process.
Keywords :
CMOS logic circuits; annealing; circuit tuning; hafnium compounds; CMOS source/drain activation process; annealing; hafnium compounds; stacking; Annealing; CMOS technology; Dielectrics; Etching; Hafnium compounds; Laboratories; MOSFET circuits; Microelectronics; Silicon; Stacking; CMOS; Fermi level pinning; HfLaO; high- $kappa$ dielectric; interdiffusion; metal gate; work function;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2007.911608
