AVS 50th International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeP

Paper TF-WeP23
Analysis and Modeling of Low Pressure CVD of Phosphorus-doped Poly-silicon in Commercial Scale Reactor

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: R. Shimizu, Fuji Electric Corporate Research and Development, Ltd., Japan
Authors: R. Shimizu, Fuji Electric Corporate Research and Development, Ltd., Japan
M. Ogino, Fuji Electric Corporate Research and Development, Ltd., Japan
M. Sugiyama, University of Tokyo, Japan
Y. Shimogaki, University of Tokyo, Japan
Correspondent: Click to Email
Poly-silicon is a key material for all kinds of semiconductor devices. The main issue for its deposition technology is how to get the uniform deposition rate and dopant concentration on silicon wafers. In this work, to investigate the poly-silicon CVD mechanisms that control the uniformity in a commercial scale LPCVD reactor, we analyzed the elementary reaction of silane based CVD with the doping gas of phosphine. We used longitudinal type CVD reactor of 6inch manufacturing scale. Under the standard condition, sample wafers were fully charged with a spacing of 4.1mm and the 100% silane and 0.8% phosphine gases with nitrogen carrier gas were introduced to the reactor. The growth temperature was kept 550°C along 700mm length hot-zone and the total pressure was 100Pa in the reactor. On the basis of the diffusion model of chemical species into the wafer-gaps, two precursors were found to contribute the profile of deposition rate, and their sticking probabilities were deduced together with the one of silane. The activation energy of direct surface reaction and gas phase reaction rate constant of silane were experimentally derived from the dependencies of the deposition rate on the growth temperature and wafer spacing, respectively. The diffusion model also gave the relative concentration distributions of the two precursors, which were examined with the elementary reaction analysis based on the Ho's model.@footnote 1@ The effect of phosphine gas on the silane reaction was found to be rather large notwithstanding the small concentration of phosphine gas, as in the studies by others.@footnote 2@ The analysis of this phenomenon will show the detail of the chemical reaction system composed of silane and phosphine gases, and give us a useful predictive model of poly-silicon CVD process. @FootnoteText@ @footnote 1@P. Ho, M. E. Coltrin, and W. G. Breiland, J. Phys. Chem., 98, 10138 (1994)@footnote 2@B. S. Meyerson and W. Olbricht, J. Electrochem. Soc., 131, 2361 (1984).