IN-SITU FOURIER-TRANSFORM INFRARED-SPECTROSCOPY AND STOCHASTIC MODELING OF SURFACE-CHEMISTRY OF AMORPHOUS-SILICON GROWTH

We present a combined experimental and theoretical study of the format ion of silicon hydride surface species during the F-2 laser (157 nm) c hemical vapor deposition of amorphous hydrogenated silicon (a-Si:H). A one-dimensional stochastic model has been applied to simulate the gro wing surface. The predictions of the model were compared to the result s of Fourier transform infrared transmission spectroscopy providing su bmonolayer resolution, We present a qualitative analysis of the bondin g configuration in the initial stage of film growth on H-terminated Si (111). The high sensitivity and resolution of the spectroscopic method allowed us to distinguish between four surface species by a deconvolu tion of the observed feature around 2100 cm(-1) during the deposition process. The theoretical results for the evolution of the different su rface species and bulk hydrogen are in close agreement with these spec tra. Consistence between mass spectrometric data and simulation was al so achieved for the growth rate and bulk hydrogen content as a functio n of disilane partial pressure and laser intensity. The good agreement between experiment and simulation obtained in this work indicates tha t it is possible to describe the main features of the complex chemical system of the growing film with a model based on a few dominant surfa ce reactions. (C) 1998 American Institute of Physics. [S0021-8979(98)0 0611-2]