Role of gas phase reactions in silicon chemical vapor deposition from monosilane

A simple flow reactor experiment is described which measures the gas phase reaction contribution to silicon chemical vapor deposition from SiH4. The approach uses the fact that the rate constant for SiH4 homogeneous decomposition exhibits a linear total pressure dependence in the low-pressure chemical vapor deposition (LPCVD) regime. Gas phase reaction channels are found to be significant even under silicon LPCVD conditions.