Composite substrate

A composite substrate manufactured by bonding method comprising sequentially order steps of:

• preparing a piezoelectric material substrate;
• preparing a silicon (Si) wafer having an interstitial oxygen concentration of 2 to 10 parts per million atomic (ppma) as a support substrate;
• bonding the piezoelectric material substrate and the silicon wafer;
• and
• thinning the piezoelectric material substrate after the bonding to form the composite substrate,
• wherein the preparing further comprises providing an intervening layer on either or both surfaces of the piezoelectric material substrate and the silicon wafer prior to the bonding;
• wherein the composite substrate comprises:
• the support substrate consisting of the silicon (Si) wafer having the interstitial oxygen concentration of 2 to 10 parts per million atomic (ppma);
• and
• the piezoelectric material substrate provided on the support substrate.