Abstract: A piezoelectric vibrator includes a thin quartz plate portion for generating vibrations, and non-contact electrodes for applying an alternating electric field. The electrodes are arranged on opposing sides of the thin quartz plate portion so as to not contact with the thin quartz plate portion. The electrodes may be formed on a supporter which can be bonded directly to the thin quartz plate. The electrodes may also be formed above the thin quartz plate and supported by the plate outside the thin quartz plate portion. The piezoelectric vibrator has a superior Q of resonance at high frequencies.

Abstract: An optical waveguide device comprises a first transparent dielectric substrate having a predetermined index of refraction and a predetermined coefficient of thermal expansion, and a second transparent dielectric substrate having the same index of refraction and coefficient of thermal expansion as the first transparent dielectric substrate. An intervening layer having an index of refraction smaller than the index of refraction of the first and second transparent dielectric substrates is interposed between the first and second transparent dielectric substrates. An optical waveguide path is formed in at least either of the first and second transparent dielectric substrates.

Abstract: In a surface acoustic wave (SAW) filter, on a 36.degree. Y-cut X-propagation lithium tantalate substrate, series branch SAW resonators, which are connected in series between an input terminal and an output terminal, and parallel branch SAW resonators, which are connected between respective pairs of the series branch resonators by wirings and which are grounded, are provided. Two series branch resonators and one parallel branch resonator are connected in a T shape, so as to form a fundamental unit. In the SAW filter, three fundamental units are serially connected. An interdigital transducer (IDT) included in each resonator is made of a metal film containing aluminum as the main component. The thickness of the metal film is in the range of 8% to 10% of the electrode pitch of the IDT of the parallel branch resonator.

Abstract: A three electrode type SAW longitudinal coupling filter includes a piezoelectric substrate having an electromechanical coupling factor (K.sup.2) higher than 10% and, three sets in total of input electrodes and output electrodes. Each of the electrodes includes a plurality of a electrode fingers of comb shape and are formed on the piezoelectric substrate. Reflectors are disposed at opposite sides of the input electrodes and output electrodes. The number of pairs of electrode fingers of the input electrodes is differentiated from the number of pairs of electrode fingers of the output electrodes. By the above arrangement, a large pass-band width can be obtained with small ripples and with an increase of the attenuation amount outside the band region.

Abstract: An optical waveguide device including a support substrate, a glass substrate, and a thin film layer formed on at least one of the substrates, if required. The support substrate and the glass substrate are bonded through direct bonding, and the glass substrate includes an optical waveguide as a part thereof. A layer having a refractive index lower than that of the glass substrate may be formed on the glass substrate. A method for fabricating such an optical waveguide device is also provided.

Abstract: This invention provides a surface acoustic wave device mounted module which is miniature, light, and highly reliable. The surface acoustic wave device mounted module also has excellent frequency characteristics. The surface acoustic wave device mounted module includes a multilayer substrate which has at least one layer of a shield pattern, input-output electrodes, grounding electrodes, through holes used for connecting electrodes, and a surface acoustic wave element. The surface acoustic wave element has metallic bumps, which are transfer-coated with a conductive resin, on electrode pads and an insulating resin around the surface acoustic wave element. The electrode pads are input-output terminals and grounding terminals formed on the surface acoustic wave element. Continuities between the input-output terminals and the input-output electrodes, and between the grounding terminals and the grounding electrodes are established by the through holes.

Abstract: A surface acoustic wave device includes: a holding substrate; a piezoelectric substrate; an interdigital transducer formed on the holding substrate; and supports for holding said piezoelectric substrate on the holding substrate so that the interdigital transducer is evenly in contact with the piezoelectric substrate.

Abstract: In a surface acoustic wave-semiconductor composite device such as a surface acoustic wave convolver, a piezoelectric plate and a semiconductor plate are layered directly or with a gap between them. Input electrodes are provided to apply a plurality of input signals to the piezoelectric plate to excite surface acoustic waves, while an output electrode is provided to detect a convolution output signal of a change in electric potential of the semiconductor plate at an interface of the semiconductor plate with the piezoelectric plate. In the layered structure, the semiconductor plate is bonded directly to the piezoelectric plate by hydrogen bonds between hydroxyl groups or by covalent or ionic bonds of oxygen atoms with component atoms of the piezoelectric and semiconductor plates. In modified structures, an inorganic thin film is applied to one of the piezoelectric and semiconductor plates, while the inorganic thin film is bonded directly to the other of the two plates.

Abstract: A surface acoustic wave device includes: a single crystal piezoelectric substrate; a single crystal piezoelectric thin plate formed on the single crystal piezoelectric substrate, the single crystal piezoelectric thin plate being bonded to the single crystal piezoelectric substrate by direct bonding; and interdigital transducers formed on the single crystal piezoelectric thin plate, for exciting a surface acoustic wave in at least the single crystal piezoelectric thin plate.

Abstract: An optical waveguide device comprises a first transparent dielectric substrate having a predetermined index of refraction and a predetermined coefficient of thermal expansion, and a second transparent dielectric substrate having the same index of refraction and coefficient of thermal expansion as the first transparent dielectric substrate. An intervening layer having an index of refraction smaller than the index of refraction of the first and second transparent dielectric substrates is interposed between the first and second transparent dielectric substrates. An optical waveguide path is formed in at least either of the first and second transparent dielectric substrates.

Abstract: An optical guided-wave device with an electro optic effect is comprised of first and second substrates having first and second refractive indices wherein the second refractive index is larger than the first one. These substrates are made of a single crystal dielectric material such as lithium tantalate or lithium niobate and, if they are made of the same material, they have different crystal orientations resulting in different refractive indices. These substrates are physically bonded directly or via a thin film such as glass, silicon, silicon oxide or silicon nitride and then, the second substrate is thinned and worked to form a wave guide therein.

Abstract: A high frequency ceramic multi-layer substrate includes a stripline embedded between two dielectric layers having ground electrodes at the top surface and at the bottom surface thereof and an electric circuit formed on another dielectric layer applied to one of the ground electrodes. The stripline is connected to the electric circuit through via holes provided through the dielectric layers. The equivalent length from the stripline to the electric circuit is a fourth of the wavelength of an input high frequency signal, to result in a high frequency attenuation circuit. Another high frequency ceramic multi-layer substrate further includes another electrode provided via another dielectric layer of larger dielectric constant to form a capacitor with one of the ground electrodes, and another dielectric layer for forming an electric circuit thereon is applied to the electrode. The stripline is connected to the electric circuit through via holes provided through dielectric layers.

Abstract: An optical waveguide device comprises a first transparent dielectric substrate having a predetermined index of refraction and a predetermined coefficient of thermal expansion, and a second transparent dielectric substrate having the same index of refraction and coefficient of thermal expansion as the first transparent dielectric substrate. An intervening layer having an index of refraction smaller than the index of refraction of the first and second transparent dielectric substrates is interposed between the first and second transparent dielectric substrates. An optical waveguide path is formed in at least either of the first and second transparent dielectric substrates.

Abstract: A dummy emitter is formed in the portion corresponding to an emitter region, on a multiplayer structural material comprising layers for forming emitter, base and collector, and using it as mask, an external base region is exposed by etching, and a projection of emitter region is formed, while the dummy emitter is inverted into an emitter electrode, thereby forming an emitter electrode metal layer to cover the whole upper surface of the emitter. Using thus formed emitter electrode metal layer, a base electrode metal layer is formed, by self-alignment, adjacently to the emitter.

Abstract: In a matching circuit for a high-frequency transistor, using a microstrip line for the main line and having a high-frequency transistor side main line shaped in a taper form, a thin-film capacitor and a grounding circuit are disposed between the taper part and the ground. The length of the parts of the thin-film capacitor is different in the signal traveling directions or the shape of the grounding circuit is different so that the impedance is matched at the output position of the thin-film capacitor part, while the spatial phase difference of high-frequency signals can be compensated at the same time.

Abstract: A semiconductor device of a multilayer structure comprising semiconductor materials of different properties manufactured by using at least a step of epitaxially forming a semiconductor material layer on a substrate and a passivation film layer thereover, a step of introducing impurities into specific portions of the epitaxially formed semiconductor material layer and a step of removing the passivation film layer formed directly above the epitaxially formed semiconductor material layer within an epitaxial device and then applying epitaxial growing. Impurities introduced additionally to specific portions of the layer inside are substantially eliminated at the boundary adjacent the layer above the region introduced with impurities and the properties of the thus-produced semiconductors vary abruptly at the boundary between the layer in which the impurities are introduced and the layer thereabove.

Abstract: A semiconductor laser apparatus includes a semiconductor laser for emitting a light beam. The semiconductor laser has, as an external cavity, a quadruple light wave mixing optical phase conjugate element for inverting a spatial phase of an incident light beam. The apparatus further includes a pair of pump light sources which are arranged such that a superimposed portion of spectra of wavelengths of three light beams including two pump light beams emitted from the pair of pump light sources and entering into the optical phase conjugate element and another light beam emitted from the semiconductor laser is narrower than the spectral width of wavelengths of each of the three light beams. This enables the laser apparatus to generate an oscillating output wavelength of extremely narrow spectral width.

Abstract: A dummy emitter (a dummy collector, in an inverted type) is formed in the portion corresponding to an emitter (a collector, in the inverted type) region, on a multiplayer structural material including layers for forming emitter, base and collector, and using it as mask, an external base region is exposed by etching, and a projection of the emitter (the collector, in the inverted type) region is formed, while the dummy emitter (the dummy collector, in the inverted type) is inverted into an emitter (a collector, in the inverted type) electrode, thereby forming an emitter (a collector, in the inverted type) electrode metal layer covering the whole upper surface of the emitter (the collector, in the inverted type). Using the thus formed emitter (the collector, in the inverted type) electrode metal layer, a base electrode metal layer is formed, by self-alignment, adjacent to the emitter (the collector, in the inverted type).

Abstract: A thin-film capacitor which has excellent withstand voltage characteristic, dielectric loss characteristic and production yield can be obtained by forming its dielectric film with a 3-layered structure comprising a first silicon oxide film formed on a polycrystalline sintered body substrate by a chemical vapor-phase deposition method, a second silicon oxide film formed by coating on the first silicon oxide film a solution state silicon oxide precursor followed by denaturing by heat treatment, and a third silicon oxide film formed on the second silicon oxide film by a chemical vapor-phase deposition method. A hybrid microwave integrated circuit is manufactured in which the above-mentioned thin-film capacitors are used as input/output coupling and DC blocking capacitors, bypass capacitors and impedance matching capacitors.

Abstract: A heterojunction bipolar transistor having excellent high-frequency characteristics is manufactured by forming a semi-insulating semiconductor layer on a collector (or emitter) layer, removing a part of the semi-insulating semiconductor layer to form a cut portion so that the collector layer is exposed at the cut portion, growing a base layer on the semi-insulating semiconductor layer, on a slant wall of the cut portion and on the exposed part of the collector layer, and growing an emitter (or collector) layer on the base layer. A base layer may be preliminarily formed on the semi-insulating semiconductor layer before forming the cut portion. Energy band gap of the emitter is greater than that of the base.