Disclose is a method for fabricating a semiconductor device. The method includes: forming a groove such as by etching one side surface of a first substrate; attaching a second substrate including a silicon layer on the etched surface of the first substrate formed with the hollow groove; etching the second substrate so as to leave substantially only the silicon layer; forming a thin film structure on the surface of silicon layers of the second substrate; and separating the second substrate formed with the thin film structure from the first substrate. For example, the groove structure may be formed in the lower portion of the device in the process of fabricating the semiconductor device to facilitate the final device separation.