Epitaxial Growth of SOS Films with Amorphous Si Buffer Layer

Abstract

A new method of SOS epitaxial growth is proposed for the improvement of the crystalline quality. The method consists of two process steps: (1) a sapphire surface is first covered with a thin amorphous Si layer prepared by sputtering, and (2) Si CVD is then carried out, which effectively avoids various problems which occur in the early stage of film growth. We have succeeded in obtaining the epitaxial layer of Si on the sapphire substrate covered with an amorphous Si buffer layer (less than 100 Å). A smooth surface of silicon is obtained on the buffer layer in spite of a slow growth rate (∼550 Å/min), a high growth temperature (∼1000°C), and a thin film thickness (0.38–0.66 µm).