Tohoku University

Piezo Studio Inc.

Kenji Inoue

Akira Yoshikawa

Yuji Ohashi

Kei Kamada

Yuui Yokota

Shunsuke Kurosawa

Yasuhiro Shoji

Yu Igarashi

Mototaka Arakawa

Tetsuo Kudo

Akihiro Yamaji

Masatoshi Ito

Hiroyuki Amano

The present invention makes clear and defines a congruent composition of a langasite-based oxide, and establishes a method of manufacturing a crystal by any desired composition of AEME(GaAl)SiO(AE is an alkaline-earth metal, ME is Nb or Ta, 0&#x2264;x&#x2264;1, &#x2212;0.5&#x3c;a&#x2264;0 or 0&#x3c;a&#x3c;0.5, &#x2212;0.5&#x3c;b&#x2264;0 or 0&#x3c;b&#x2264;0.5, and &#x2212;0.5&#x3c;c&#x2264;0 or 0&#x3c;c&#x3c;0.5, excluding a=b=c=0). This makes it possible to suppress the formation of an impurity, and improve the yield and crystal manufacturing rate. The raw material is a raw material mixture prepared by mixing an alkaline-earth metal or its carbonate or oxide, Nb or Ta or its oxide, Ga or its oxide, Al or its oxide, and Si or its oxide.

Crystal material and method of manufacturing the same

To provide a vibrator made of a piezoelectric crystal having a larger electromechanical coupling coefficient and a more satisfactory frequency-temperature characteristic than those of quartz, a vibrating piece () is made of a CaTa(GaAl)SiOsingle crystal (0&#x3c;x&#x2264;1). In the single crystal, letting &#x3b8; be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 18x+17.5&#x2264;&#x3b8;&#x2264;24x+24.5 is set. In addition, the vibrating piece () is made of a CaNb(GaAl)SiOsingle crystal (0&#x3c;x&#x2264;1). In the single crystal of this arrangement, letting &#x3b8; be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 25x+23.083&#x2264;&#x3b8;&#x2264;32x+26.167 is set.

Piezoelectric vibrator and sensor

To improve the Q value of a piezoelectric thin-film element in a state in which unnecessary vibration is suppressed, an acoustic reflection film () is affixed to a first electrode (), a piezoelectric single-crystal substrate () is thinned by polishing from the other surface () of the piezoelectric single-crystal substrate (), such that the first electrode () and piezoelectric thin film () are piled on the piezoelectric single-crystal substrate (). In this polishing, a pressure (polishing pressure) to the surface () during polishing in an electrode formation region where the first electrode () is formed differs from that in a non-electrode formation region around the electrode formation region. Consequently, the electrode formation region of the piezoelectric thin film (), where the first electrode () is formed, is made thinner than the non-electrode formation region around the electrode formation region.

Method for manufacturing piezoelectric thin-film element

Growing community of inventors

Sendai, Japan

Kenji Inoue