Symposium on Process Physics and Modeling in Semiconductor Technology 1990
Conference paper

Mechanisms and models of Si film growth from SiH4 and Si2H6


Mechanisms of silicon CVD film growth in the absence of gas phase reactions have been studied for both SiH4 and Si2H6 precursors using a combination of surface science experiments and kinetic modeling. The decomposition of both molecules on clean single crystal Si surfaces has been investigated under UHV conditions. A stepwise mechanism for SiH4 decomposition has been determined from these experiments. This mechanism is used in a surface chemical kinetic model of very low pressure CVD Si growth which accurately predicts literature data for both Si growth rate and hydrogen surface coverage measured versus temperature. The disilane case is considerably more complex than silane due to competing parallel reactions. Certain features of the Si2H6 mechanism have been identified, and trends in experimental data are qualitatively fit by our kinetic model. Rapid desorption of a SiH4 product, and slow desorption of H2 products are observed.