Substrate, manufacturing method of substrate, saw device and device

Abstract

Provided is a substrate that can be made to have a suitable strength with low-cost and that can be bonded firmly to a piezoelectric substrate. The substrate, which is for SAW devices, consists of spinel, and the PV value of the difference in level of one of the main faces of the substrate is 2 nm to 8 nm inclusive. The average roughness (Ra) value of the one of the main faces of the substrate is preferably 0.01 nm to 3.0 nm inclusive, more preferably 0.01 nm to 0.5 nm inclusive. Also the Young's modulus of the spinel substrate, which is for the SAW device or other devices, is preferably 150 GPa to 350 GPa inclusive.

Dependencies are inferred from the claim text.