Title :
The Impact of Stacked Cap Layers on Effective Work Function With HfSiON and SiON Gate Dielectrics
Author :
Cho, Hag-Ju ; Yu, Hong Yu ; Chang, Vincent S. ; Akheyar, Amal ; Jakschik, Stefan ; Conard, Thierry ; Hantschel, Thomas ; Delabie, Annelies ; Adelmann, Christoph ; Elshocht, Sven Van ; Ragnarsson, Lars-Ake ; Schram, Tom ; Absil, Philippe ; Biesemans, Serge
Author_Institution :
Samsung Electron., Hwasung
fDate :
7/1/2008 12:00:00 AM
Abstract :
Cap layers have been used to modulate the effective work function (EWF) for high- /metal-gate CMOS devices. We have investigated the impact of stacking cap layers on the EWF. Stacked cap layers consisting of two sequential cap layers, including, Al2O3, Dy2O3, Sc2O3 and La2O3, were formed on HfSiON or SiON as host dielectrics. It is demonstrated that the EWF change due to the stacked cap layers corresponds to the sum of the EWF change from each single cap layer. Furthermore, no host dielectric dependence on the shifts is observed. This behavior is attributed to the complete intermixing of the stacked cap layers with the host dielectrics.
Keywords :
MOS capacitors; aluminium compounds; dielectric materials; dysprosium compounds; hafnium compounds; high-k dielectric thin films; lanthanum compounds; mixing; scandium compounds; silicon compounds; work function; HfSiON-Al2O3; HfSiON-Al2O3-La2O3; HfSiON-La2O3; NMOS capacitors; SiON-Al2O3; SiON-Al2O3-Dy2O3; SiON-Al2O3-Sc2O3; SiON-Dy2O3; effective work function; gate dielectrics; high-k dielectrics; intermixing; stacked cap layer; Aluminum oxide; Dielectric devices; Hafnium; High K dielectric materials; High-K gate dielectrics; MOS devices; MOSFETs; Semiconductor device manufacture; Stacking; Threshold voltage; Cap layer; HfSiON; SiON; effective work function (EWF); high-$k$ dielectric; intermixing; metal gate; stacked cap layer;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2008.923317
