AVS 53rd International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS1-FrM

Paper PS1-FrM1
Subplantation and Interface Modification during Ion Assisted Low-Pressure Plasma Deposition of Oxides at the RF-Biased Electrode

Friday, November 17, 2006, 8:00 am, Room 2009

Session: Plasma-Surface Interactions III
Presenter: L. Martinu, Ecole Polytechnique de Montreal, Canada
Authors: A. Amassian, Cornell University
P. Desjardins, Ecole Polytechnique de Montreal, Canada
L. Martinu, Ecole Polytechnique de Montreal, Canada
Correspondent: Click to Email
Significant research effort has been devoted to linking plasma characteristics, ion-surface interactions, and film properties in PVD, PECVD, and hybrid PECVD/PVD processes, leading to a qualitative understanding of surface processes and thin film growth mechanisms. In this paper, we report on the sub-surface effects of subplantation in an O@sub 2@ RF discharge during plasma treatment and thin film deposition at the RF-biased electrode. Using in situ real-time spectroscopic ellipsometry (RTSE), we have obtained time-resolved quantitative information about depth-dependent modifications of c-Si(001) exposed to intense ion bombardment under conditions typically used for oxide deposition. RTSE analysis indicates almost immediate damage formation (<1s) to a depth of a few nanometers below the surface. Oxide growth is detected immediately after (>1 to 2s); it forms near the surface of the target on top of an O deficient interfacial damage layer (DL). Both layers experience a self-limiting growth behavior, as oxide and DL thicknesses reach bias-dependent saturation values, determined by the maximum ion penetration depth. The results are independently confirmed by cross-sectional high resolution TEM analysis. The in situ experimental study was complemented by Monte-Carlo TRIDYN simulations based on the binary collision approximation, which were modified to calculate dynamic changes in the structure and composition of a target exposed to a broad-energy ion source (ion energy distribution at RF electrode) at high fluence. This novel approach has allowed us to obtain the first quantitatively accurate simulation results of ion bombardment-induced sub-surface oxygen incorporation on time-scales from <<1s up to a few minutes. We will illustrate the effects of subplantation with the use of practical examples, such as interface broadening in TiO@sub 2@/SiO@sub 2@ multilayers, density and interface control in dense-porous Si@sub 3@N@sub 4@ multilayer devices, and other film systems.