IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Dielectrics Monday Sessions
       Session DI1-MoP

Paper DI1-MoP12
Diffusion Studies of High k Gate Dielectric Candidates Hafnium and Zirconium Silicates into Si

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: High K Dielectrics Poster Session
Presenter: M.A. Quevedo-Lopez, University of North Texas
Authors: M.A. Quevedo-Lopez, University of North Texas
M. El-Bouanani, University of North Texas
S. Addepalli, University of North Texas
C. Huang, University of North Texas
J.L. Duggan, University of North Texas
B.E. Gnade, University of North Texas
R.M. Wallace, University of North Texas
L Colombo, Texas Instruments Inc.
M. Bevan, Texas Instruments Inc.
M. Douglas, Texas Instruments Inc.
M. Visokay, Texas Instruments Inc.
Correspondent: Click to Email
The area of advanced gate dielectrics has gained considerable attention recently because the SIA technology roadmap predicts the need for a <2.0 nm SiO@sub 2@ gate dielectric for sub-0.13 mm scaled silicon CMOS.@footnote 1@ Desirable properties for new gate dielectrics include; higher permittivity (@kappa@) than SiO@sub 2@ (@kappa@ = 3.9), minimal reaction barrier, thermodynamic stability in direct contact with silicon, low leakage current (<1 A/cm@super 2@ at 1V), and very low diffusion into silicon. Considering these requirements, Hf silicate and Zr silicate have been proposed as suitable candidates for advanced gate dielectric applications.@footnote 2,3@ However, more issues have to be resolved. Among those issues metal diffusion (Zr, Hf) into the channel is critical because impurity diffusion from the gate dielectric into the channel region would likely result in deleterious effects on carrier mobility. We have studied the diffusion of Hf and Zr from high-@kappa@ gate dielectric candidates HfSixOy and ZrSixOy. The studies were carried out after aggressive thermal annealing followed by chemical etching. The annealed/etched films were studied using monochromatic X-ray Photoelectron Spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), High resolution TEM, and Rutherford Backscattering Spectrometry (RBS). Film deposition, chemical etching and characterization issues are discussed. No detectible Hf diffusion into Si from RTP and furnace-annealed films is observed. In contrast Zr diffusion is observed upon RTP and furnace anneals. Implications for high-k gate dielectric applications are also discussed. This work was supported by the Texas Advanced Technology Program, the Semiconductor Research Corporation, and DARPA. @FootnoteText@@footnote 1@Semiconductor Industry Association roadmap 1999 @footnote 2@G.D. Wilk and R.M. Wallace, Appl. Phys. Lett. 74, 2854 (1999). @footnote 3@G.D. Wilk and R.M. Wallace, Appl. Phys. Lett. 76, 112 2000). @footnote 4@W.-J. Qi, et al., Appl. Phys. Lett. 77, 1704 (2000).