Abstract: An array of thin film piezoelectric resonators are formed on a substrate and connected in parallel to form a single piezoelectric resonator with enhanced piezoelectric coupling. The array includes a first conductive layer positioned on the substrate and defining a first electrode, a plurality of columns of piezoelectric material positioned on the conductive layer and each defining a separate piezoelectric resonator, and a second conductive layer positioned on the plurality of columns and defining a second electrode. The columns are selectively deposited or deposited as a single layer and etched into columns.

Abstract: A monolithic thin film resonator, lattice filter including spaced apart strips of a conductive film positioned on a substrate so as to define a first set of I/O terminals, a layer of piezoelectric material positioned on the conductive film, and spaced apart conductive strips of a conductive film positioned on the piezoelectric layer orthogonal to the first strips to form cross-over areas, each defining a thin film resonator and a second set of I/O terminals. A plurality of portions of a dielectric film are positioned on selected cross-over areas to mass load the thin film resonators so as to lower the resonant frequency.

Abstract: A heterojunction bipolar transistor having a planar surface topology, reduced lateral dimensions and a base electrode aligned to both the emitter and collector electrodes is fabricated by forming sub-collector, collector, base and one or more emitter layers on a substrate. An opening extending to the sub-collector layer is then formed and a first portion of the collector electrode is formed therein so that the sidewalls of the opening are not contacted by the first portion. Dielectric material is then formed between the sidewalls of the opening and the first portion of the collector electrode. A second portion of the collector electrode is then formed on the first portion of the collector electrode along with an emitter electrode so that the second portion of the collector electrode and the emitter electrode are substantially planar. After then exposing the base layer, the self-aligned base electrode is formed between the second portion of the collector electrode and the emitter electrode.