METHOD FOR PRODUCING COMPOSITE WAFER PROVIDED WITH OXIDE SINGLE-CRYSTAL THIN FILM

摘要

Provided is a composite wafer in which cracking and peeling are unlikely to occur in the bonding interface between a support wafer and an oxide single-crystal thin film, and in which a single-crystal thin film that is lithium tantalite or lithium niobate is transferred onto the entire surface of the support wafer. Specifically, a method for producing a composite wafer includes at least: a step in which hydrogen atom ions or hydrogen molecule ions are injected from the surface in order to form an ion injection layer inside of an oxide single-crystal wafer; a step in which surface activation treatment is performed on at least one of the surface of the oxide single-crystal wafer into which ions have been injected and the surface of the support wafer; a step in which the surface of the oxide single-crystal wafer into which ions have been injected and the surface of the support wafer are bonded to obtain a joined body; a step in which the joined body is subjected to heat treatment at a temperature that is 90 °C or more and that does not cause cracking; and a step in which ultrasonic vibration is applied to the joined body that has been subjected to heat treatment, peeling is carried out along the ion injection layer, and an oxide single-crystal thin film that is transferred onto the support wafer is obtained.