AVS 47th International Symposium
    Material Characterization Monday Sessions
       Session MC-MoM

Paper MC-MoM6
XPS Characterization of NO Oxynitride Films using Chemical Profiling

Monday, October 2, 2000, 10:00 am, Room 207

Session: Depth Profiling
Presenter: I.S. Choi, Hyundai Electronics Industries Co., Ltd., Korea
Authors: I.S. Choi, Hyundai Electronics Industries Co., Ltd., Korea
H.J. Kim, Hyundai Electronics Industries Co., Ltd., Korea
S.Y. Lee, Hyundai Electronics Industries Co., Ltd., Korea
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For the fabrication of MOS devices, the incorporation of nitrogen into thin SiO2 dielectric films has been shown to improve the electrical and structural property of the films. Some benefits of these oxynitrides are as following: (a) resistance to boron diffusion, (b) immunity to hot carrier effects, (c) higher charge-to-breakdown voltage, and (d) reduced charge trapping. These improvements are owing to accumulation of nitrogen atoms at the dielectric/silicon interface. The depth profile and chemical environment of nitrogen in oxynitride films is a critical information to the process control so that a lot of technique to study this material have long been used.@footnote 1,2,3@ However, Ar ion sputtering usually used to acquire depth profile may affect the actual concentration and the bond characteristic of N. In this X-ray photoelectron spectroscopic study of oxynitride films, we adopted successive delicate etching of the films with dilute HF solution as a technique for profiling. It was believed that this kind of chemical profiling would not affect the actual concentration and chemical environment of the films. The etch step was finely controlled to have etch rate of ~0.5 ¢®?/sec and the thickness of every slicely etched films were measured by XPS. With the help of this chemical profiling technique, we observed, for the first time, the selectivity of the etch rate between the thermal oxide and oxynitride films. Much difference between the etch rate of two films was used to remove upper oxide layer and study remained pure oxynitride film. Therefore we could directly observe the thickness of NO oxynitride interlayer to be about 6¢®?.@footnote 4@ We also have studied the bond structure, thickness, and composition of the oxynitride layers by deconvoluting Si2p and N1s XPS spectra. The results of the study on the composition and the chemical environment of the oxynitride films will be discussed in this presentation. @FootnoteText@ @footnote 1@ Rama I.Hegde, Philip J. Tobin, Kimberly G. Reid, Bikas Maiti, and Sergio A. Ajuria, Appl. Phys. Lett. 66(21), 2882 (1995) @footnote 2@ E. P. Gusev, H. C. Lu, T. Gustafsson, E. Garfunkel, M. L. Green, and D.Brasen, J. Appl. Phys. 82(2), 896 (1997) @footnote 3@ M. R. Frost, C. W. Magee. Appl. Surf. Sci. 104/105, 379 (1996) @footnote 4@ E. A. Irene, Q. Liu, W. M. Paulson, P. J. Tobin, and R. I. Hegde, J. Vac. Sci. Technol., B14, 1697 (1996)