The invention provides a method for preparing a thin film heterostructure. The method comprises the steps of providing a
wafer substrate with an injection surface; conducting
ion injection from the injection surface on the
wafer substrate to form an injection defect layer at the predetermined depth of the
wafer substrate; providing a support substrate, and performing temperature rising bonding onthe support substrate and the wafer substrate; annealing a obtained structure to form a continuous defect layer; stripping part of the wafer substrate through external force assisting, and forming wafer film on the wafer substrate to obtain a thin film heterostructure including the support substrate and the wafer film. The method can reduce the
thermal strain of a bonding structure through the temperature rising bonding, so that the bonding structure remains stable and complete in the high-temperature process, and avoid the problem of film
cracking caused by thermal mismatch in the stripping process, the bonding structure is separated from the continuous defect layer through the external force assisting method, so that no effect is caused on a bonding interface, and an external force assisting stripping method can reduce stripping temperature and stripping time, thereby reducing the
cumulative effect of thermal stress in a piezoelectric
crystal.