ArF excimer laser induced photolytic growth of Si homoepitaxial films from Si2H6 at 330 °C

Abstract

This letter discusses low-temperature Si homoepitaxy on Si(100) substrates by the photolytic decomposition of Si2H6 by the 193 nm emission of an ArF excimer laser. The chemical vapor deposition process at growth rates from 0.5–4 Å/min is performed in an ultrahigh vacuum chamber which, along with an ex situ HF dip and a novel in situ hydrogen clean using laser excitation, results in minimization of oxygen and carbon contamination which inhibits Si epitaxy. The growth involves photolytic decomposition of Si2H6 and the generation and adsorption of SiH2 precursors on the hydrogenated Si surface, which is the rate limiting step. Very low defect density films in terms of stacking faults and dislocation loops (less than 106 cm−2), and excellent crystallinity have been grown at 330 °C and 0.5 W laser power, as confirmed by Schimmel etching and Nomarski microscopy, transmission electron microscopy, electron diffraction and in situ reflection high-energy electron diffraction.