Growth and characterization of silicon thin films employing supersonic jets of SiH4 on polysilicon and Si(100)

Supersonic jets of silane were employed to deposit silicon on both polysilicon and Si(100) at substrate temperatures ranging from 500 to 650 °C. The growth rate and film uniformity were studied as a function of silane kinetic energy. Increasing the SiH4 precursor kinetic energy from 0.4 eV (10% SiH4 in He mixture) to 1 eV (1% SiH4 in H2 mixture) results in as much as an order of magnitude increase in reaction probability. The advantage of using high kinetic energy precursors to enhance deposition is reflected in the centerline growth rates obtained employing supersonic jets of SiH4. At higher substrate temperatures, the high kinetic energy SiH4 jet has a higher growth rate than the low kinetic energy SiH4 jet, although, the flux of the high energy jet at the centerline is a factor of 8 less than the flux of the low energy jet. The silane flux distribution from the supersonic jet is dependent on the gas mixture; a flux distribution of cos55 θ results from the 1% silane in hydrogen jet (1 eV) compared to a cos28 θ distribution from the 10% silane in helium jet (0.4 eV).