Epitaxial wafer

Abstract

An improved and highly productive method is proposed for the preparation of an epitaxial wafer (EPW) consisting of a single crystal silicon wafer as the substrate having a mirror-polished surface and an epitaxial layer of silicon formed on the mirror-polished surface of the substrate by the method of vapor-phase growing. Different from conventional methods in which the mirror-polishing of the substrate surface is conducted in several steps including, usually, the primary, secondary and finish polishing steps taking a great deal of labor and time, it has been unexpectedly discovered that an EPW having excellent properties not inferior to those conventional EPWs can be obtained by conducting the mirror-polishing with the primary polishing only omitting the subsequent steps provided that the thus mirror-polished surface of the substrate has a surface roughness RMS in the range from 0.3 to 1.2 mm.

Dependencies are inferred from the claim text.