Murata Manufacturing Co., Ltd.

Jun Koike

Hideharu Ieki

A ZnO/sapphire substrate includes an R-plane sapphire substrate whose (0 1-1 2) planes are parallel to the surface thereof and a ZnO epitaxial film formed on the R-plane sapphire substrate. The (1 1-2 0) planes of the ZnO epitaxial film are disposed with an interplanar spacing in the range of about 1.623 to 1.627 &angst; parallel to the (0 1-1 2) planes of the R-plane sapphire substrate.

ZnO/sapphire substrate and method for manufacturing the same

A SAW device formed by providing at least one interdigital transducer on a piezoelectric substrate which is prepared by forming a (1120) ZnO piezoelectric thin film on a (0112) plane .alpha.-Al.sub.2 O.sub.3 substrate, and forming reflectors on both sides of the interdigital transducer along a surface wave propagation direction. Each of the reflectors is so structured that a ratio H/.lambda. of its thickness H to a wavelength .lambda. of a surface wave is in a range of 0.015 to 0.041.

Surface acoustic wave filter with an optimizing reflector

When a zinc oxide piezoelectric crystal film is epitaxially grown on an R-plane sapphire substrate by sputtering, a target containing not more than 4.5 percent by weight of Cu with respect to the total content of Zn and Cu is employed so that the zinc oxide piezoelectric film contains Cu. Thus, it is possible to obtain a zinc oxide piezoelectric crystal film having excellent orientation.

Zinc oxide piezoelectric crystal film on sapphire plane

Disclosed herein is a zinc oxide piezoelectric crystal film which is grown on an R-plane sapphire substrate to orient its c-axis in parallel with the substrate surface. In order to improve orientation of the zinc oxide piezoelectric crystal film used is a Zn target for forming the zinc oxide piezoelectric crystal film by sputtering contains not more than 5 percent by weight of nickel or not more than 4.5 percent by weight of iron with respect to Zn.

Growing community of inventors

Kyoto, Japan

Jun Koike