AVS 45th International Symposium
    Thin Films Division Wednesday Sessions
       Session TF-WeA

Paper TF-WeA9
Microcrystalline Silicon Thin Films Deposited By Low Temperature Reactive Magnetron Sputtering: The Effect Of Using Deuterium vs. Hydrogen

Wednesday, November 4, 1998, 4:40 pm, Room 310

Session: Advances in Sputtering
Presenter: J.E. Gerbi, University of Illinois, Urbana-Champaign
Authors: J.E. Gerbi, University of Illinois, Urbana-Champaign
D.S. Kim, SAIT, Korea
G. Ben Amor, Ecole Polytechnique, France
J.R. Abelson, University of Illinois, Urbana-Champaign
Correspondent: Click to Email
Microcrystalline silicon (uc-Si:H) thin films are of interest for macro-electronic technologies: they can serve as optical absorber or doped contact layers in solar cells, or as the nucleation layer in the direct deposition of polycrystalline silicon on glass for thin film transistors.@footnote 1@ The grain size, shape, and defect density significantly modify the electronic properties of uc-Si:H; therefore, it is highly desirable to control the film microstructure through the growth process. We previously showed that DC reactive magnetron sputtering (RMS) of a Si target produces uc-Si:H films when sufficient H@sub 2@ is added to the Ar working gas. In the sputtering plasma, H@sub 2+@ ions are accelerated towards the Si target and reflect as fast neutral H atoms, which impinge on the growing film and implant to a depth of ~ 50Å. This large flux of fast H atoms provides unique control over the nucleation and growth of the uc-Si:H phase.@footnote 2@ In this work, we explore the effects of using D@sub 2@ instead of H@sub 2@ to grow uc-Si:H films on glass at a substrate temperature of 230°C. The substitution of D@sub 2@ for H@sub 2@ lowers the partial pressure at which the microcrystalline regime is entered, and produces films with a higher degree of crystallinity throughout the entire pressure range investigated. Crystalline nucleation and the grain-size dependent electronic structure are observed in real time using spectroscopic ellipsometry. We report post-deposition TEM, Raman spectroscopy, and electrical characterizations. To explain the implantation-related isotope effect, we present binary collision (TRIM) simulations of the energy distribution, range, and recoil behaviors of the H vs. D neutral fluxes, and their resultant dynamic concentrations in the film. @FootnoteText@ @Footnote 1@Y. H. Yang and J. R. Abelson, Appl. Phys. Lett. 67, 3623 (1995). @Footnote 2@Y. H. Yang, M. Katiyar, N. Maley, and J. R. Abelson, Appl. Phys. Lett. 65(14), 1769 (1994).