A transistor formed on a monocrystalline Si wafer is temporarily transferred onto a first temporary supporting substrate. The first temporarily supporting substrate is heat-treated at high heat so as to repair crystal defects generated in a transistor channel of the monocrystalline Si wafer when transferring the transistor. The transistor is then made into a chip and transferred onto a TFT substrate. In order to transfer the transistor which has been once separated from the monocrystalline Si wafer, a different method from a stripping method utilizing ion doping is employed.