Piezoelectric assembly and process of forming a piezoelectric assembly

A process of forming a piezoelectric assembly, comprising:

• providing a base metal substrate having a main substrate surface;
• forming a first seed layer comprising a first material of crystalline perovskite structure represented by the general formula ABO3 on the main substrate surface, the forming comprising the acts of
• depositing a first seed layer solution comprising ions of A and B on the main substrate surface, wherein the first seed layer is prepared as a layered structure including the acts of
• depositing a first seed layer solution comprising ions of A and B,
• forming a dense seed sub-layer comprising a first pyrolysis procedure, characterized by a first pyrolysis temperature T1 and a first holding time t1 at the first pyrolysis temperature T1,
• depositing a second seed layer solution comprising ions of A and B,
• forming a porous seed sub-layer comprising a second pyrolysis procedure, characterized by a second pyrolysis temperature T2, and a second holding time t2 at the second pyrolysis temperature T2, and
• crystallization of the perovskite structure by a first annealing procedure,
• forming a first piezoelectric layer comprising a piezoelectric material of crystalline perovskite structure comprising lead, and comprising the acts of
• depositing a piezoelectric layer solution comprising lead-ions and further ions of the piezoelectric material, and
• crystallization of the perovskite structure comprising lead by a second annealing procedure.

A piezoelectric assembly, comprising:

• a base metal substrate having a main substrate surface;
• a first oriented layer arranged on the main substrate surface, the first oriented layer comprises a first material of crystalline perovskite structure which constitutes at least 90 wt % of the first oriented layer;
• and
• a first piezoelectric layer is arranged on the first oriented layer, the first piezoelectric layer comprises a piezoelectric material of crystalline perovskite structure comprising lead, the piezoelectric material has a larger longitudinal piezoelectric coefficient (d33) along a direction of the unit cells of the piezoelectric material than the first material of the first oriented layer, and wherein a degree of orientation “o” of the piezoelectric material of the first piezoelectric layer is 90% or more, the degree of orientation “o” is the average degree of alignment of the direction of the unit cells of the crystalline piezoelectric material with a local surface normal “N” of the main substrate surface,
• wherein the substrate has a second substrate surface opposite to the main substrate surface, and wherein a layered structure comprising a second piezoelectric layer on a second oriented layer is arranged on the second substrate surface in analogy to the first piezoelectric layer on the first oriented layer on the main substrate surface,
• wherein the first oriented layer comprises a porous oriented sub-layer which has a porous structure with a relative porosity of up to 70%,
• wherein the first oriented layer further comprises a dense oriented sub-layer, the porous oriented sub-layer having a concentration of pores at least two times higher than a concentration of pores of the dense oriented sub-layer, and
• wherein the dense oriented sub-layer is arranged directly on the main substrate surface and the porous oriented sub-layer is arranged on the dense oriented sub-layer.

A piezoelectric assembly, comprising

• a base metal substrate having a main substrate surface;
• a first oriented layer arranged on the main substrate surface, the first oriented layer comprises a first material of crystalline perovskite structure which constitutes at least 90 wt % of the first oriented layer;
• and
• a first piezoelectric layer is arranged on the first oriented layer, the first piezoelectric layer comprises a piezoelectric material of crystalline perovskite structure comprising lead, the piezoelectric material has a larger longitudinal piezoelectric coefficient (d33) along a direction of the unit cells of the piezoelectric material than the first material of the first oriented layer, and wherein a degree of orientation “o” of the piezoelectric material of the first piezoelectric layer is 90% or more, the degree of orientation “o” is the average degree of alignment of the direction of the unit cells of the crystalline piezoelectric material with a local surface normal “N” of the main substrate surface,
• wherein a second oriented layer consisting of the first material is arranged above the first piezoelectric layer, a second piezoelectric layer is arranged on the second oriented layer, wherein the second piezoelectric layer comprises the same piezoelectric material with the same degree of orientation “o” of 90% or more as the first piezoelectric layer,
• wherein the first oriented layer comprises a porous oriented sub-layer which has a porous structure with a relative porosity of up to 70%,
• wherein the first oriented layer further comprises a dense oriented sub-layer, the porous oriented sub-layer having a concentration of pores at least two times higher than a concentration of pores of the dense oriented sub-layer, and
• wherein the dense oriented sub-layer is arranged directly on the main substrate surface and the porous oriented sub-layer is arranged on the dense oriented sub-layer.