Piezoelectric thin-film element and piezoelectric thin-film device
There is provided a piezoelectric thin film element, comprising: a substrate 1 ; and a piezoelectric thin film 3 having an alkali niobium oxide-based perovskite structure represented by a composition formula (K 1-x Na x ) y NbO 3 provided on the substrate 1 , wherein a carbon concentration of the piezoelectric thin film 3 is 2×10 19 /cm 3 or less, or a hydrogen concentration of the piezoelectric thin film 3 is 4×10 19 /cm 3 or less.
1. A piezoelectric thin film element, comprising:
a substrate; and
a piezoelectric thin film having an alkali niobium oxide-based perovskite structure represented by a composition formula (K 1-x Na x ) y NbO 3 (satisfying 0.4≦x≦0.7 and 0.75≦y≦0.90) provided on the substrate,
wherein a carbon concentration of the piezoelectric thin film is 2×10 19 /cm 3 or less, and a hydrogen concentration is 4×10 19 /cm 3 or less.
2. The piezoelectric thin film element according to claim 1 , wherein the piezoelectric thin film has a pseudo-cubic structure and is preferentially oriented in (001) plane direction.
3. The piezoelectric thin film according to claim 2 , wherein a base layer is provided between the substrate and the piezoelectric thin film.
4. The piezoelectric thin film according to claim 3 , wherein the base layer is a Pt layer, and the Pt layer is preferentially oriented in (111) plane direction.
5. The piezoelectric thin film according to claim 2 , wherein the substrate is a Si substrate, a surface oxide film-attached Si substrate, or a SOI substrate.
6. A piezoelectric thin film device, comprising:
the piezoelectric thin film element of claim 2 ;
an upper electrode and a lower electrode provide in an upper part and in a lower part, with the piezoelectric thin film of the piezoelectric thin film element interposed between them; and
a function generator or a voltage detector connected between the upper electrode and the lower electrode.
7. The piezoelectric thin film according to claim 1 , wherein a base layer is provided between the substrate and the piezoelectric thin film.
8. The piezoelectric thin film according to claim 7 , wherein the base layer is a Pt layer, and the Pt layer is preferentially oriented in (111) plane direction.
9. The piezoelectric thin film according to claim 1 , wherein the substrate is a Si substrate, a surface oxide film-attached Si substrate, or a SOI substrate.
10. A piezoelectric thin film device, comprising:
the piezoelectric thin film element of claim 1 ;
an upper electrode and a lower electrode provide in an upper part and in a lower part, with the piezoelectric thin film of the piezoelectric thin film element interposed between them; and
a function generator or a voltage detector connected between the upper electrode and the lower electrode.