Patent ID: 9553253
Date: 2017-01-24
CPC Classifications: C23C,H01L,H03H

Claim:
1. A method for manufacturing a composite substrate of a piezoelectric device comprising: an ion implantation step of implanting ions into a piezoelectric substrate to form an ion implantation layer at a depth within the piezoelectric substrate; a sacrificial layer formation step of forming an electrically conductive sacrificial layer on a first main surface of the piezoelectric substrate that is closer to the ion implantation layer than a second main surface of the piezoelectric substrate opposed to the first main surface; a supporting layer bonding step of bonding a supporting layer to the first main surface of the piezoelectric substrate on which the electrically conductive sacrificial layer has been formed; a heated detachment step of detaching a portion of the piezoelectric substrate in which the ion implantation layer has been formed by heating the piezoelectric substrate, the detached portion of the piezoelectric substrate being a piezoelectric thin film that has the electrically conductive sacrificial layer formed on the first main surface; and a polarizing upper electrode formation step of forming a polarizing upper electrode on a surface of the piezoelectric thin film; and a polarization step of polarizing the piezoelectric thin film by applying an electric field to the piezoelectric thin film; wherein the supporting layer provided during the supporting layer bonding step, is capable of supporting the piezoelectric thin film; in the polarization step, the electrically conductive sacrificial layer is used as an electrode, which consists of the electrically conductive sacrificial layer, to which the electric field is applied, and the polarizing upper electrode is connected to the electrically conductive sacrificial layer by an electric field applying circuit configured to apply the electric field; and in the sacrificial layer formation step, the electrically conductive sacrificial layer is arranged to be removed in a subsequent step so as not to be included in the piezoelectric device that includes the composite substrate finally produced by the method.