| 摘要 |
Disclosed is a piezoelectric device free of some problems associated with ion implantation: the degradation of the surface roughness of the piezoelectric thin film and the cracking of the supporting substrate. Also disclosed is a method for manufacturing this piezoelectric device. During an isolation formation step a supporting substrate (50) has a piezoelectric thin film (10) formed on its front (14) with a compressive stress film (90) present on its back (15). The compressive stress film (90) compresses the surface (14 on the piezoelectric single crystal substrate (1) side of the supporting substrate (50), and the piezoelectric thin film (10) compresses the back (15) of the supporting substrate (50), which is opposite to the surface (14) on the piezoelectric single crystal substrate (1) side. In other words, the compressive stress produced by the compressive stress film (90) and that by the piezoelectric thin film (10) are in balance in the supporting substrate (50). This makes the supporting substrate (50) free of warpage and able to remain flat. To this end, the driving force that induces isolation in the isolation formation step is gasification of the implanted ionized element rather than the compressive stress to the isolation plane produced by the piezoelectric thin film (10). |
