PIEZOELECTRIC SINGLE CRYSTAL WAFER

摘要

PROBLEM TO BE SOLVED: To provide a piezoelectric single crystal wafer for an elastic surface wave or pseudo-elastic surface wave device having remarkably decreased small foreign materials attached to the surface for forming an electrode and the crack of the wafer and provide a piezoelectric single crystal wafer giving a filter, etc. having excellent characteristics in high production yield. SOLUTION: The surface roughness Ra of the outer circumference to form an electrode for the transmission and reception of elastic surface wave or pseudo-elastic surface wave and excluding the surface and back face of the wafer is adjusted to <=2.3μm.