Sumitomo Electric Industries, Limited

Nec Corporation

Research Institute of Innovative Technology for the Earth

Shin-ichi Shikata

Hideaki Nakahata

Kenjiro Higaki

Satoshi Fujii

Yoshiki Nishibayashi

Hiromu Shiomi

Hiroyuki Kitabayashi

Akihiro Hachigo

Tadashi Tomikawa

Yuichiro Seki

Tomoki Uemura

Naoji Fujimori

Kentaro Yoshida

Akihiko Ikegaya

Keiichiro Tanabe

Masashi Narita

Yasushi Yamamoto

Yoshihiro Takahashi

Takeshi Kobayashi

Hidenori Nakanishi

Naohiro Toda

Natsuhiko Sakairi

Itozaki Hideo

Surfaces of diamond crystals are examined by coating the surfaces with thin metal films, launching laser beams to the diamond surfaces in a slanting angle, detecting defects and particles on the diamond surfaces by the scattering of beams and counting the defects and particles by a laser scanning surface defect detection apparatus. Diamond SAW devices should be made on the diamond films or bulks with the defect density less than 300 particles cm . Preferably, the diamond,surfaces should have roughness less than Ra20 nm. Diamond SAW filters can be produced by depositing a piezoelectric film and making interdigital transducers on the low-defect density diamond crystals.

Diamond wafer, method of estimating a diamond wafer and diamond surface acoustic wave device

A surface-acoustic-wave (SAW) device that has not only an increased propagation velocity of SAWs but also an increased electromechanical coupling coefficient of 20% or more. The SAW device comprises a diamond substrate , a KNbO layer , and IDTs . The KNbO layer is composed of a single crystal having the layer thickness and the crystal orientation that are controlled so as to obtain a propagation velocity of 5,000 m/s or more and an electromechanical coupling coefficient of 20% or more for the SAW in a specified mode.

Surface-acoustic-wave device

Surfaces of diamond crystals are examined by coating the surfaces with thin metal films, launching laser beams to the diamond surfaces in a slanting angle, detecting defects and particles on the diamond surfaces by the scattering of beams and counting the defects and particles by a laser scanning surface defect detection apparatus. Diamond SAW devices should be made on the diamond films or bulks with the defect density less than 300 particles cm,. Preferably, the diamond surfaces should have roughness less than Ra20 nm. Diamond SAW filters can be produced by depositing a piezoelectric film and making interdigital transducers on the low-defect density diamond crystals.

A diamond wafer including a substrate and a (100) oriented polycrystalline diamond film grown on the substrate for making surface acoustic wave devices, semiconductor devices or abrasion-resistant discs. The (100) oriented film is produced by changing a hydrocarbon ratio in a material gas halfway from a higher value to a lower value. The wafer is monotonously distorted with a distortion height H satisfying 2 .mu.m.ltoreq..vertline.H.vertline..ltoreq.150 .mu.m. The film is polished to a roughness of less than Rmax50 nm and Ra20 nm.

Diamond wafer and method of producing a diamond wafer

A surface acoustic wave device includes at least diamond, a single crystal LiNbO.sub.3 layer formed on the diamond, and an interdigital transducer formed in contact with the LiNbO.sub.3 layer and uses a surface acoustic wave (wavelength: .lambda..sub.n .mu.m) in an nth-order mode (n=1 or 2). When the thickness of the LiNbO.sub.3 layer is t.sub.1 (.mu.m), kh.sub.1 =2.pi.(t.sub.1 /.lambda..sub.n) and the cut orientation (.theta., .PHI., and .psi. represented by an Eulerian angle representation) with respect to the crystallographic fundamental coordinate system of the LiNbO.sub.3 layer are selected from values within specific ranges. Consequently, a surface acoustic wave device which increases the propagation velocity (V) of a surface acoustic wave and improves the electromechanical coupling coefficient (K.sup.2) is realized.

Surface acoustic wave device incorporating single crystal LiNbO.sub.3

A diamond heat sink is disclosed in this invention. The diamond heat sink has a support layer consisting of substantially undoped vapor phase synthetic diamond, a heat sensitive layer consisting of doped vapor phase synthetic diamond formed on the surface of the support layer; an insulation layer consisting of substantially undoped vapor phase synthetic diamond formed on a predetermined region of the heat sensitive layer; and an electrode formed on the heat sensitive layer. The electrode typically consists of a metal, preferably Ti/Mo/Au or Ti/Pt/Au. The diamond heat sink of the present invention may further include a highly-doped layer for creating Ohmic contacts with the metal electrode, which is made of the vapor phase synthetic diamond having high impurity levels, and which is disposed between the metal electrode and the heat sensitive layer.

Method of forming diamond heat sink comprising synthetic diamond film

A first surface acoustic wave device for 2nd mode surface acoustic wave of a wavelength .lambda. (.mu.m) according to the present invention is a SAW device of 'type A' device shown in FIG. 6A, wherein a parameter kh3=2.pi.(t.sub.A /.lambda.) is: 0.033.ltoreq.kh3.ltoreq.0.099, and wherein a parameter kh1=2.pi.(t.sub.Z /.lambda.) and a parameter kh2=2.pi.(t.sub.S /.lambda.) are given within a region ABCDEFGHIJKLA in a two-dimensional Cartesin coordinate graph of FIG. 1.

Diamond-ZnO surface acoustic wave device

A micro mechanical component of the present invention comprises a base, and at least one drive portion supported on the base and relatively driving to the base, in which the drive portion is formed from a diamond layer. Thus, because the drive portion has excellent mechanical strength and modulus of elasticity, the operational performance can be greatly improved as a micro mechanical component processed in a fine shape, from the conventional level. Further, because the drive portion exhibits excellent device characteristics under severe circumstances, the range of applications as a micro mechanical component can be widely expanded from the conventional range.

Micro mechanical component and production process thereof

A field effect transistor in accordance with the present invention comprises a buffer layer made of a highly resistant diamond on a substrate; an active layer which is made of a conductive diamond on the buffer layer and has such a dopant concentration that conduction of carriers is metallically dominated thereby and such a thickness that dopant distribution is two-dimensionally aligned thereby; a cap layer made of a highly resistant diamond on the active layer; a gate electrode layer formed on the cap layer so as to make Schottky contact therewith; and a source electrode layer and a drain electrode layer which make ohmic contact with a laminate structure of said buffer, active and cap layers. Namely, the active layer is formed as a so-called .delta.-dope layer or pulse-dope layer doped with a conductive dopant, while being held between both highly resistant buffer and cap layers. Accordingly, even when the dopant concentration in the conductive diamond layer is increased, a high gain, as an excellent controllability and an excellent temperature-stability in operation characteristics can be obtained.

Field effect transistor using diamond

A diamond base material for surface acoustic wave device, which includes: a low-resistivity base material, and a high-resistivity diamond layer having a thickness of 5-50 .mu.m disposed on the low-resistivity base material.

Surface acoustic wave device and diamond base material for the same

A surface acoustic wave device comprises a diamond layer (12) or a substrate (11) with a diamond layer (12) formed thereon, an Al electrode (13) formed on the diamond layer (12), and a ZnO piezoelectric thin film layer (14) formed on the diamond layer (12) with the Al electrode (13) covered by the ZnO piezoelectric thin film layer (14). The ZnO piezoelectric thin film layer (14) has a thickness h1 within a range defined by 0.65.ltoreq.kh1.ltoreq.0.75 while the Al electrode (13) has a thickness h2 within a range defined by 0.03.ltoreq.kh2.ltoreq.0.04, where k is given by k=2 .pi./.lambda. and .lambda. represents an electrode period.

Surface acoustic wave device

A diamond heat sink of the present invention comprises: a support layer consisting of substantially undoped diamond; a heat sensitive layer consisting of doped diamond, disposed on the surface of the support layer; an insulation layer consisting of substantially undoped diamond, disposed on a predetermined region in the surface of the heat sensitive layer; electrodes disposed on the heat sensitive layer, wherein an exothermal device is placed on the surface of the insulation layer; and a cooling structure disposed on the backside of the support layer, the cooling structure having at least one microchannel, the microchannel being defined by a diamond, wherein an exothermal device is to be placed on the surface of the insulation layer; and wherein the heat sensitive layer and the electrodes form a thermistor, the electrical resistivity of the thermistor being capable of varying corresponding to heat generated from the exothermal device and transferred through the insulation layer to the thermistor.

Diamond heat sink including microchannel therein and methods for

A field emission device according to the present invention comprises a support substrate; a cathode mounted on a surface of said support substrate; a first diamond portion located on any surface of said substrate, said first diamond portion substantially having an electrical connection with said cathode; a second diamond portion located on the substrate surface on which said first diamond portion is also located, said second diamond portion including plurality of diamond protuberances; and an anode positioned spaced apart from said first and second diamond portions, wherein a space is formed between said anode and said second diamond portion.

Growing community of inventors

Itami, Japan

Shin-ichi Shikata