Abstract: The present invention is intended to provide a thin film bulk acoustic wave resonator, which has a resonant excitation portion free from damage caused by etching, a high electromechanical coupling coefficient kt2 and a high quality coefficient Q value, and to provide a thin film bulk acoustic wave resonator having a plurality of different resonant frequencies, which can be formed on the same substrate without increasing number of lithography process. An internal cavity is provided in a semiconductor or insulative substrate such as crystal silicon. The thin film bulk acoustic wave resonator has a layered member comprising a first electrode film, a piezoelectric film and a second electrode film on a thin wall of e.g. single crystal over the internal cavity.

Abstract: A voltage controlled oscillator includes a resonator configured to resonate with an initial oscillation frequency during starting period of oscillation and a steady oscillation frequency during a steady state oscillation. The resonator includes a film bulk acoustic resonator having a series resonance frequency higher than the steady oscillation frequency. A negative resistance circuit configured to drive the resonator, has a positive increment for reactance in the steady state oscillation compared with reactance in the starting period.

Abstract: To provide a miniaturized voltage controlled oscillator which can oscillate simultaneously a plurality of frequencies and has high stability of frequency, an excellent low phase noise, small variation per hour, and a wide frequency variable range. A thin film bulk acoustic wave resonator using single crystal ferroelectric material equal to or smaller than 10 &mgr;m in thickness whose direction of polarization is aligned to the direction of thickness is utilized as the piezoelectric member. The voltage controlled oscillator having large changing rate of the oscillation frequency of 0.01%/V or more and an extremely small phase noise is provided by changing the voltage applied to the electrodes.

Abstract: A piezoelectric thin film resonator which comprises a first electrode, a second electrode, and a piezoelectric film which is interposed between the first electrode and the second electrode, and formed of an epitaxial ferroelectric thin film containing barium titanate, a spontaneous polarization of the epitaxial ferroelectric thin film being uniaxially orientated in a direction normal to a film surface.

Abstract: The present invention is intended to provide a thin film bulk acoustic wave resonator, which has a resonant excitation portion free from damage caused by etching, a high electromechanical coupling coefficient kt2 and a high quality coefficient Q value, and to provide a thin film bulk acoustic wave resonator having a plurality of different resonant frequencies, which can be formed on the same substrate without increasing number of lithography process.

Abstract: To provide a miniaturized voltage controlled oscillator which can oscillate simultaneously a plurality of frequencies and has high stability of frequency, an excellent low phase noise, small variation per hour, and a wide frequency variable range. A thin film bulk acoustic wave resonator using single crystal ferroelectric material equal to or smaller than 10 &mgr;m in thickness whose direction of polarization is aligned to the direction of thickness is utilized as the piezoelectric member. The voltage controlled oscillator having large changing rate of the oscillation frequency of 0.01%/V or more and an extremely small phase noise is provided by changing the voltage applied to the electrodes.

Abstract: A high frequency filter comprises thin film piezoelectric resonators connected in series between the input/output nodes, thin film piezoelectric resonators connected in parallel between the input/output nodes and a variable voltage circuit adapted to change the voltage applied to at least either the thin film piezoelectric resonators connected in series or the thin film piezoelectric resonators connected in parallel. The resonance characteristic of at least either the thin film piezoelectric resonators connected in series or the thin film piezoelectric resonator connected in parallel is shifted by changing the voltage applied by the variable voltage circuit to change the pass characteristic of the filter.

Abstract: A piezoelectric thin film resonator which comprises a first electrode, a second electrode, and a piezoelectric film which is interposed between the first electrode and the second electrode, and formed of an epitaxial ferroelectric thin film containing barium titanate, a spontaneous polarization of the epitaxial ferroelectric thin film being uniaxially orientated in a direction normal to a film surface.

Abstract: A ferroelectric capacitor comprising an Si substrate, a lower electrode including a metal film containing Ir or Rh and epitaxially grown on the Si substrate, and a conductive oxide film having a perovskite crystal structure and epitaxially grown on the metal film, a perovskite type ferroelectric thin film epitaxially grown on the lower electrode, and an upper electrode formed on the ferroelectric thin film. Alternatively, the lower electrode may be formed of a structure which comprises a silicide film represented by a chemical formula MSi2 (wherein M is at least one kind of transition metal selected from nickel, cobalt and manganese) and epitaxially grown on the Si substrate, a metal film containing Ir or Rh and epitaxially grown on the silicide film, and a conductive oxide film having a perovskite crystal structure and epitaxially grown on the metal film.

Abstract: A sputtering system comprises: a substrate holder for holding a substrate; and a cathode having a magnet therein and holding a target, the cathode being off-axis aligned with respect to the substrate. The cathode may comprise a plurality of cathodes, each of which has a flat backing plate, and two targets supported on both sides of the backing plate, the target being off-axis aligned with respect to the thin-film deposited surface of the substrate. The target may be supported on the side surface of a cylindrical or prismatic cathode body having a magnet therein, and the target being off-axis aligned with respect to the thin-film deposited surface of the substrate.