Epitaxial semiconductor wafer and a manufacturing method thereof

摘要

An epitaxial semiconductor wafer having a wafer substrate made of semiconductor single crystal, an epitaxial layer deposited on a top surface of said wafer substrate and a polysilicon layer deposited on a back surface of said wafer substrate. The semiconductor single crystal is exposed in a region defined within a distance of at least 50 mum from a ridge line as a center, which is defined as an intersection line between said back surface and a bevel face interconnecting said top surface and said back surface of said wafer substrate. The polysilicon layer is 1.0 to 2.0 mum thick. The epitaxial layer is 1.0 to 20 mum thick. The wafer substrate is a silicon single crystal.