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.

Evaluation of piezoresistivity properties of sputtered ZnO thin films

“…On the other hand, few studies report the piezoresistive characteristics of ZnO. This may be attributed to the following reasons: (a) the piezoelectric properties of ZnO are well documented in the literature [4][5][6] ; (b) compared to SiC 7 and diamond, ZnO exhibits lower electromechanical properties.…”

Investigation of laser-ablated ZnO thin films grown with Zn metal target: A structural study

“…This semiconductor is very attractive because it has many applications such as transparent conductive contacts, solar cells, laser diodes, ultraviolet lasers, thin films transistors and others [2][3][4][5][6][7][8] .…”

Shear Mode Piezoelectric Thin Film Resonators

“…However, the combinations of the shear mode piezoelectric film and substrate are limited due to the lattice mismatch. a-plane ZnO or AlN/r-plane sapphire (Mitsuyu et al, 1980;Wittstruck et al, 2003), a-plane ZnO/42º Y-X LiTaO 3 (Nakamura et al, 2000) where c-axis in the film is parallel to the substrate plane have been reported. Ion beam orientation control technique (Yanagitani & Kiuchi, 2007c), which enables in-plane and out-of-plane orientation without use of epitaxial growth, is introduced in the third section.…”