Provided is a method for manufacturing a low-cost bonded
wafer (8) which allows bulk crystals of a
wide bandgap semiconductor (1) to be transferred onto a
handle substrate (3) as thinly as possible without breaking the substrate. More specifically, provided is a method for manufacturing a bonded
wafer (8) by forming a
wide bandgap semiconductor film (4) on a surface of a
handle substrate (3), the method comprising a step of implanting ions from a surface (5) of a
wide bandgap semiconductor substrate (1) having a bandgap of 2.8 eV or more to form an
ion-implanted layer (2), a step of applying a surface activation treatment to at least one of the surface of the
handle substrate (3) and the
ion-implanted surface (5) of the wide bandgap
semiconductor substrate (1), a step of bonding the surface (5) of the wide bandgap
semiconductor substrate (1) and the surface of the handle substrate (3) to obtain bonded substrates (6), a step of applying a heat treatment to the bonded substrates (6) at a temperature of 150° C. or more and 400° C. less, and a step of subjecting the
ion-implanted layer (2) of the wide bandgap
semiconductor substrate (1) to
irradiation of visible light from the semiconductor substrate (1) side of the bonded substrates (6) to embrittle an interface of the ion-implanted layer (2) and transfer the wide bandgap semiconductor film (4) onto the handle substrate (3).