SOS SUBSTRATE HAVING LOW DEFECT DENSITY IN THE VICINITY OF INTERFACE

摘要

The problem of a defect density increase due to lattice constant mismatch between silicon and sapphire is solved, and an SOS substrate having a low surface detect density even in an extremely thin silicon film is provided. The bonded SOS substrate (8) has a semiconductor thin film (4) provided on the surface of a sapphire substrate (3). The bonded SOS substrate is obtained by means of: a step wherein the sapphire substrate (3) and a semiconductor substrate (1) are provided; a step wherein an ion implanted layer (2) is formed by implanting ions from the surface of the semiconductor substrate (1); a step wherein surface activation treatment is performed to said surface of the sapphire substrate (3) and/or the semiconductor substrate (1) surface having the ions implanted therein; a step wherein the semiconductor substrate (1) surface and the sapphire substrate (3) surface are bonded at 50-350°C; and a step wherein a bonded body (6) is obtained by performing heat treatment at a highest temperature of 200-350°C to the bonded substrate; and a step wherein the bonded body (6) is disposed at a temperature higher than the bonding temperature, visible light is applied toward the ion implanted layer (2) of the semiconductor substrate (1) from the sapphire substrate (3) side or the semiconductor substrate (1) side, the interface of the ion implanted layer (2) is made brittle, and the semiconductor thin film (4) is transferred.