High Quality Silicon Epitaxy at 500°C using Silane Gas-Source Molecular Beam Technique

Abstract

High-quality silicon epitaxial films were successfully obtained at as low as 500°C using a SiH₄ molecular beam technique in a UHV system. Perfect selective growth onto SiO₂-patterned wafers, which allowed a precise measurement on epitaxial film thickness through the height of the step formed by the selective growth, was also observed. Detailed Arrhenius plots on the growth rate were thus obtained for the temperature range 500–800°C. The plots showed a break around 600°C, separating a lower- and a higher-temperature region with activation energies of 21 kcal/mol and 3.6 kcal/mol, respectively. Growth rate measurements with the silane pressure varied for 2.0, 3.0, and 4.0×10^-4 Torr revealed first-order reaction kinetics for the lower-temperature region and a second-order nature for the higher-temperature region.