Structures and SAW properties of rf-sputtered single-crystal films of ZnO on sapphire

Abstract

Single-crystal films of ZnO have been epitaxially grown on the (0001) and (011̄2) planes of sapphire by rf sputtering. Crystalline structures and electrical properties of the films were investigated. Surface acoustic wave (SAW) properties, including a phase velocity, a coupling coefficient, a propagation loss, and a temperature coefficient of delay, were measured for SAW propagating along the c-axis of the ZnO films, on the (011̄2) planes of sapphire. Availability of this structure for high-frequency SAW devices has been demonstrated by a filter with a 1050-MHz center frequency.