High-Growth-Rate Chemical Vapor Deposition of Silicon: an Experimental and Modeling Approach

Abstract

Abstract The chemical vapor deposition (CVD) process of silicon from silane has been analyzed by a combined experimental and modeling approach with the aim to optimize growth rate, yield and deposition quality of polycystalline silicon while minimizing gas phase nucleation. The effects of precursor concentration, flow rate and buffer gas have been investigated. Modeling of the gas phase and of the deposition process has been used in a parameter screening to select appropriate deposition conditions in a stagnation-point cold-wall CVD reactor. Deposition experiments have been performed for several silane concentrations with helium, nitrogen and hydrogen as the buffer gases. Polycrystalline films of good quality were obtained with growth rates up to 8 μm/min. The observed trends in the experiments are in good qualitative agreement with model predictions. To achieve high film growth rates and minimal gas phase nucleation, hydrogen is suggested as the diluent gas, potential reasons for this being its involvement in gas phase and surface reactions.