IDT electroded piezoelectric diaphragms
AssigneesThe Penn State Research Foundation, Northrup Grumman Corporation
InventorsSusan Trolier-McKinstry, Eunki Hong, Carl Freidhoff, Silai Krishnaswamy
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Abstract
The disclosed invention relates to achieving micromachined piezoelectrically-actuated diaphragms. The piezoelectric diaphragm includes a central, inactive electrode free region and an annular shaped interdigitated electrode adjacent to the outer periphery of the central region. The diaphragm also may have an inactive annular, electrode free region and an active central, interdigitated electrode region. The diaphragms may be used in, such as, miniature pumps. The pumps may include a plurality of chambers to generate peristaltic pumping of fluids.
Claims24
A piezoelectric diaphragm having an improved deflection in response to an applied voltage, the diaphragm comprising
- a piezoelectric or antiferroelectric layer having an upper surface and a lower surface, and an annular region bordering a central region on the upper surface of the diaphragm,
- the annular region being in an active state when the central region is in an inactive state and the annular region being in an inactive state when the central region is in an active state,
- wherein the active state is present in any one of the annular region or central region when an interdigitated electrode is present that region,
- the interdigitated electrode comprising a composite metal layer that includes an adhesion promoting metal layer in contact with the piezoelectric layer and a highly conductive metal layer in contact with the adhesion promoting layer, and
- wherein when a region is in an inactive state that region also is free of the composite metal layer.
A piezoelectric diaphragm having an improved deflection in response to an applied voltage, the diaphragm comprising
- a piezoelectric layer having an upper surface and a lower surface, and an annular region bordering a central region on the upper surface of the diaphragm,
- the annular region being in an active state when the central region is in an inactive state and the annular region being in an inactive state when the central region is in an active state,
- wherein the active state is present in any one of the annular region or central region when an interdigitated electrode is present that region,
- the interdigitated electrode comprising a composite metal layer that includes an adhesion promoting metal layer in contact with the piezoelectric layer and a highly conductive metal layer in contact with the adhesion promoting layer, and
- wherein when a region is in an inactive state that region also includes the composite metal layer.
A method of making an interdigitated piezoelectric diaphragm comprising,
- depositing a layer of SiO2 on a Si substrate,
- depositing a layer of ZrO2 over the layer of SiO2,
- depositing a layer of Pb(Zr0.52Ti0.48)O3 over the layer of ZrO2
- depositing a Pt layer on top of the layer of Pb(Zr0.52Ti0.48)O3,
- reactive ion etching the layer of Pt to produce an interdigitated annular electrode and a central, inactive electrode free region that is free of Pt,
- applying a pattern to the bottom surface of the substrate by photolithography to define a region that defines the diameter of the diaphragm and
- applying deep reactive ion etching to the region to release the diaphragm.
A method of making an interdigitated piezoelectric diaphragm comprising,
- depositing a layer of SiO2 on a Si substrate,
- depositing a layer of ZrO2 over the layer of SiO2,
- depositing a layer of a piezoelectric material over the layer of ZrO2
- depositing a highly conductive metal layer on top of the layer of piezoelectric material,
- reactive ion etching the metal layer to produce an interdigitated annular electrode and a central, inactive electrode free region that is free of Pt,
- applying a pattern to the bottom surface of the substrate to define a region that defines the diameter of the diaphragm and
- applying deep reactive ion etching to the region to release the diaphragm.
Dependencies are inferred from the claim text.