METHOD FOR MANUFACTURING SILICON ON INSULATOR WAFER IMPROVED IN SURFACE ROUGHNESS USING SIGE SACRIFICIAL LAYER

摘要

A method for manufacturing an SOI(Silicon On Insulator) wafer is provided to improve the surface characteristic of the SOI wafer by etching the SiGe sacrificial layer with an etchant. A SiGe layer as a sacrificial layer(110) is epitaxially formed on a silicon wafer(100). The SiGe layer has a thickness of hundreds nm to several mum. A Si layer as an SOI layer(120) is epitaxially grown. The Si layer has a thickness of hundreds nm to several mum. A Ge content of the sacrificial layer is greater than that of the SOI layer. Preferably, the Ge content of the sacrificial layer is over 5%. A separation layer is formed in the sacrificial layer through an ion implantation. Alternatively, the separation layer is formed in the silicon substrate or on a position around an interface between the silicon substrate and the sacrificial layer.