CPC H10N 30/10516 (2023.02) [H03H 3/08 (2013.01); H03H 9/02559 (2013.01); H03H 9/02834 (2013.01); H03H 9/02897 (2013.01); H03H 9/25 (2013.01); H10N 30/072 (2023.02); H10N 30/079 (2023.02); H10N 30/086 (2023.02)] | 15 Claims |
1. A composite substrate comprising:
a piezoelectric single crystal substrate;
a support substrate; and
an intermediate layer provided between the piezoelectric single crystal substrate and the support substrate, wherein
the intermediate layer is a film formed of an inorganic material, and the intermediate layer is separated into at least three layers along a bonding surface of the composite substrate, and the intermediate layer includes:
a first intermediate layer containing a thermally synthesized silica, the first intermediate layer being in contact with the support substrate;
a second intermediate layer provided on the piezoelectric single crystal substrate side of the piezoelectric single crystal substrate; and
a third intermediate layer formed of amorphous silicon,
wherein the first intermediate layer is joined to the second intermediate layer as the third intermediate layer is sandwiched between the first intermediate layer and the second intermediate layer.
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