e-Article
Widely Tunable Work Function TaN/Ru Stacking Layer on HfLaO Gate Dielectric
Document Type
Periodical
Author
Source
IEEE Electron Device Letters IEEE Electron Device Lett. Electron Device Letters, IEEE. 29(1):50-53 Jan, 2008
Subject
Language
ISSN
0741-3106
1558-0563
1558-0563
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 $^{\circ}\hbox{C}$ 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.