SOI SUBSTRATE AND METHOD FOR MANUFACTURING SOI SUBSTRATE

摘要

An oxide film (11) having a thickness t<SUB>OX</SUB> of not less than 0.2 µm is provided on a single-crystal silicon substrate (10) on its laminating face. In a method for manufacturing an SOI substrate according to the present invention, a low-temperature process is adopted for suppressing the occurrence of thermal distortion attributable to the difference in the coefficient of thermal expansion between the silicon substrate (10) and a quartz substrate (20). To this end, the thickness t<SUB>OX</SUB> of the oxide film (11) is brought to a large value of not less than 0.2 µm to impart satisfactory mechanical strength to the thin film to be separated and, at the same time, to allow strain to be absorbed in and relaxed by the relatively thick oxide film to suppress the occurrence of transfer defects during the step of separation. A substrate satisfying a relationship of 2L = t<SUB>OX</SUB>, wherein t<SUB>OX</SUB> represents the thickness of the oxide film and L represents the average ion implantation depth of the hydrogen ion-implanted layer (12), may be used as the single-crystal silicon substrate (10) to be laminated onto the quartz substrate (20).