An actuator including a unitary ceramic element capable of bending in resse to an applied voltage. The ceramic has a first region of lower resistivity in contact with a second region of higher resistivity. There is no seam where said regions contact each other. The first region contains an additive in an amount needed to reduce resistivity thereof relative to said second region. The second region is devoid of additive or contains a different additive that raises resistivity thereof or contains the same additive in a different amount than in the first region.
A piezoelectric element having a piezoelectric film where the difference in the quantity of lead along the thickness of the film is minimized. The film is obtained by first applying, at least once, a first sol for use in forming a PZT film on a substrate having a lower electrode formed thereon. Second, applying a second sol having the greater lead content than the first sol. Third, subjecting these films to heat treatment at a predetermined temperature at least once. The second sol has a composition capable of forming a piezoelectric film having a Perovskite structure expressed generally by A.sub.x B.sub.y O.sub.3, and the content of material constituting the A site of the first sol is greater than what constitutes the A site of the second sol.
A modification of the traditional unimorph flextensional actuator is provided by replacing the metal shim with an electrically conducting oxide. Comprised of lead zirconate titanate and zinc oxide that is co-sintered, the laminate composite obtains large axial displacements while maintaining moderate axial loads. The varistor properties of zinc oxide dictate that the conductance increases several orders of magnitude when a critical electric field is applied. The versatility of the processing over other actuator system facilitates miniaturization, while maintaining comparable performance characteristics. Functional gradients in the material properties are created in the green body by layering thin tape cast sheets. The unique PZT-zinc oxide composite not only controls the piezoelectric gradient, but permits control of the sintering kinetics leading to the processing of either flat or highly domed structures.
A resistive heater having a doped ceramic heating element embedded either partially or completely within a matrix of undoped ceramic material. The ceramic may be silicon carbide, and the dopant may be nitrogen. Many of the advantages of the present heater stern from the fact that the materials used for the heating elements and the matrix material surrounding those elements have substantially the same coefficient of thermal expansion. In one embodiment, the heater is a monolithic plate that is compact, strong, robust, and low in thermal mass, allowing it to respond quickly to power input variations. The resistive heater may be used in many of the reactors and processing chambers used to fabricate integrated circuits, such as those that deposit epitaxial films, and carry out rapid thermal processing.
