SUBSTRATE, SUBSTRATE PRODUCTION METHOD AND SAW DEVICE

摘要

A substrate is obtained that has suitable strength at low cost, and can tightly bond with a component such as a piezoelectric material substrate. The present invention is a SAW device substrate (1) comprising spinel, wherein the level difference PV value of one of the main surfaces (1a) of the substrate (1) is no less than 2 nm and no more than 8 nm. The value of average roughness Ra of the one main surface (1a) of the substrate (1) is preferably no less than 0.01 nm and no more than 0.5 nm. Accordingly, the main surface (1a) that bonds with the piezoelectric material substrate of the SAW device on the substrate (1) can bond satisfactorily with the piezoelectric material forming the piezoelectric materialsubstrate using van der Waals force.