AVS 53rd International Symposium
    Applied Surface Science Friday Sessions
       Session AS-FrM

Paper AS-FrM9
Back Side SIMS Depth Profile Analysis of a High-k Dielectric Material

Friday, November 17, 2006, 10:40 am, Room 2005

Session: Thin Film Characterization
Presenter: F.A. Stevie, North Carolina State University
Authors: F.A. Stevie, North Carolina State University
R. Garcia, North Carolina State University
Z. Zhu, North Carolina State University
P. Sivasubramani, University of Texas at Dallas
R.M. Wallace, University of Texas at Dallas
D.P. Griffis, North Carolina State University
Correspondent: Click to Email
Current status of the back side SIMS depth profiling method and results on a high-k dielectric material are presented. A typical concern for high-k materials is diffusion of the constituent elements into underlying silicon during CMOS activation annealing.@footnote 1@ High-k dielectric materials are difficult to depth profile from the front side because of non-uniform sputtering and the necessity to analyze an element at a trace level after profiling through a layer with a matrix level concentration of the same element. Mechanical polishing was used to reach the area of interest.@footnote 2@ A successful back side polishing experiment requires that the polished surface be flat, smooth and parallel to the front side surface with as thin a residual cover layer as possible. Analytical concerns include sample mounting, optimization of depth resolution, and control of sample charging. The material under study is HfAlON. SIMS depth profile analyses were performed using a magnetic sector CAMECA IMS-6F. Application of a ruthenium conductive layer to cap the sample not only reduced sample charging, but proved to be a good choice for adherence of the conductive layer to the sample surface and to the non-conductive mounting epoxy. Samples of the dielectric before and after 10 sec RTA anneal at 1000 °C were prepared for SIMS analysis using mechanical polishing. Neither sample showed measurable Hf or Al diffusion into the silicon substrate. @FootnoteText@ @footnote 1@ P. Sivasubramani, M. J. Kim, B. E. Gnade, R. M. Wallace, L. F. Edge, D. G. Schlom, H. S. Craft and J.-P. Maria, Applied Physics Letters 86, 201901 (2005).@footnote 2@ C. Gu, A. Pivovarov, R. Garcia, F. Stevie, D. Griffis, J. Moran, L. Kulig, and J. F. Richards, J. Vac. Sci. Technol. B22, 350 (2004).