SURFACE CLEANING METHOD OF SILICON SUBSTRATE AT LOW TEMPERATURE APPLICATION FOR MOLECULAR BEAM EPITAXY TECHNIQUE

Abstract

Silicon (Si) surface cleaning procedure by two-steps was investigated application for molecular beam epitaxy (MBE) technique. At the first step, surface sample is cleaned by chemical method to eliminate contamination of organic compound as well remove the SiO₂ native oxide which has a low surface quality. A thin SiO₂ layer is then formed to protect the Si clean surface from contamination during processing before MBE growth. At the second step, the SiO₂ thin film is eliminated from the substrate by the thermal evaporated method at high vacuum environment. Surface substrate quality is investigated by reflection high energy electron diffraction (RHEED) and Auger electron spectroscopy (AES). After cleaning, a Ge film is grown directly on Si substrate. The observation of RHEED results shows that Ge film has a good crystal quality with smooth and uniform surface. The growth mode of Ge layers corresponds to layer by layer growth (2D growth).