Piezoelectric device having an insulating portion overlapping electrode opening
A piezoelectric device includes a support member, and a vibrating portion provided on a support surface of the support member. The vibrating portion includes, in addition to a first electrode, a piezoelectric film and a second electrode arranged in a stacking direction, an insulating film configured to increase an electric resistance value between the first and second electrodes. The first electrode is provided on the support surface of the support member, and includes an opening penetrating the first electrode in the stacking direction. The piezoelectric film is provided on the first electrode to extend across the opening. The second electrode is provided on the piezoelectric film. The insulating film is provided at a position between the first electrode and the second electrode, and at least a part of the insulating film overlaps with the opening in the stacking direction.
1 . A piezoelectric device comprising:
a support member having a support surface; and
a vibrating portion stacked on the support surface in a stacking direction, wherein
the vibrating portion includes
a first electrode, a piezoelectric film and a second electrode that are arranged adjacently in the stacking direction, and an insulating portion configured to increase an electric resistance value between the first electrode and the second electrode,
the first electrode is arranged on the support surface, and is provided with (i) an opening penetrating through the first electrode in the stacking direction, and (ii) a first electrode surface that is a surface opposite to the support surface,
the piezoelectric film is provided to extend across the opening on the first electrode surface, and is provided with a piezoelectric film surface that is a surface opposite to the first electrode surface,
the second electrode is provided on the piezoelectric film surface, and
the insulating portion is provided at a position between the first electrode and the second electrode, and at least a part of the insulating portion overlaps with the opening of the first electrode in the stacking direction.
2 . The piezoelectric device of claim 1 , wherein
the insulating portion is provided on the piezoelectric film surface, and
the second electrode is provided on the piezoelectric film surface and extends across the insulating portion.
3 . The piezoelectric device of claim 1 , wherein
the piezoelectric film includes a first piezoelectric film and a second piezoelectric film arranged adjacently in the stacking direction,
the first piezoelectric film is provided on the first electrode surface, and has a first piezoelectric film surface that is a surface opposite to the first electrode surface,
the insulating portion is provided on the first piezoelectric film surface, and overlaps with an entire area of the opening in the stacking direction in a cross section taken along the opening in the stacking direction, and
the second piezoelectric film is provided on the first piezoelectric film surface and extends across the insulating portion.
4 . The piezoelectric device of claim 3 , wherein
the first piezoelectric film and the second piezoelectric film are made of materials including scandium, and
an amount of scandium per unit mass of the first piezoelectric film is smaller than an amount of scandium per unit mass of the second piezoelectric film.
5 . The piezoelectric device of claim 1 , wherein
the piezoelectric film includes a first piezoelectric film, a second piezoelectric film and a third piezoelectric film arranged adjacently in the stacking direction,
the first piezoelectric film is provided on the first electrode surface, and has a first piezoelectric film surface that is a surface opposite to the first electrode surface,
the insulating portion is provided on the first piezoelectric film surface, and overlaps with an entire area of the opening in the stacking direction in a cross section taken along the opening in the stacking direction,
the second piezoelectric film is provided on the first piezoelectric film surface to extend across the insulating portion, and includes a second piezoelectric film surface that is a surface opposite to the first piezoelectric film surface, and
the third piezoelectric film is provided on the second piezoelectric film surface.
6 . The piezoelectric device of claim 5 , wherein
the first piezoelectric film, the second piezoelectric film and the third piezoelectric film are respectively made of materials including scandium, and
an amount of scandium per unit mass of the first piezoelectric film is smaller than at least one of an amount of scandium per unit mass of the second piezoelectric film and an amount of scandium per unit mass of the third piezoelectric film.
7 . The piezoelectric device of claim 3 , wherein
the first piezoelectric film is provided with a piezoelectric film recess defining a piezoelectric film space, and the piezoelectric film recess is recessed from the first piezoelectric film surface toward the first electrode surface, and
the insulating portion is provided in the piezoelectric film space to have an insulating surface that is positioned on a side opposite to the piezoelectric film recess, the insulating surface of the insulating portion is a continuous plane as the first piezoelectric film surface.
8 . The piezoelectric device of claim 3 , wherein
the insulating portion includes:
a first expansion portion that does not overlap with the opening in the stacking direction, the first expansion portion being positioned on one side in a width direction that is orthogonal to the stacking direction in the cross section; and
a second expansion portion that does not overlap with the opening in the stacking direction, the second expansion portion being positioned on another side in the width direction, and
a size of the first expansion portion or the second expansion portion in the width direction is equal to or greater than at least four times of a dimension of the piezoelectric film in the stacking direction.
9 . The piezoelectric device of claim 3 , wherein
the second piezoelectric film has a crystal structure, and
the insulating portion includes a material that causes the crystal structure of the second piezoelectric film to have self-align characteristics.
10 . The piezoelectric device of claim 1 , wherein
the insulating portion is made of a material different from the support member, and is provided at a position corresponding to a portion where the opening is provided.
11 . The piezoelectric device of claim 1 , wherein
the insulating portion includes an amorphous film having an amorphous structure.
12 . The piezoelectric device of claim 1 , wherein
the insulating portion includes a void.
13 . A piezoelectric device comprising:
a support member having a support surface; and
a vibrating portion stacked on the support surface in a stacking direction, wherein
the vibrating portion includes
a first electrode arranged on the support surface of the support member, and provided with an opening penetrating through the first electrode in the stacking direction,
a piezoelectric film filled in the opening and arranged on a surface of the first electrode in the stacking direction to extend across the opening of the first electrode,
a second electrode arranged on the piezoelectric film in the stacking direction, and
an insulating portion disposed at a position between the first electrode and the second electrode, and configured to increase an electric resistance value between the first electrode and the second electrode, and
at least a part of the insulating portion overlaps with the opening of the first electrode in the stacking direction.
14 . The piezoelectric device of claim 13 , wherein
the insulating portion overlaps with an entire area of the opening of the first electrode in the stacking direction.
15 . The piezoelectric device of claim 13 , wherein
the piezoelectric film includes a first piezoelectric film and a second piezoelectric film arranged adjacently in the stacking direction,
the first piezoelectric film is arranged on the first electrode and filled in the opening,
the insulating portion is provided in the first piezoelectric film to have a same plan surface with a surface of the first piezoelectric film,
the insulating portion overlaps with an entire area of the opening in the stacking direction in a cross section taken along the opening in the stacking direction, and
the second piezoelectric film is provided on the first piezoelectric film surface and extends across the insulating portion.