Sumitomo Electric Industries, Limited

Tomoki Uemura

Hideaki Nakahata

Satoshi Fujii

Yuichiro Seki

Shinsuke Fujiwara

Kenjiro Higaki

Takuji Okahisa

Shin-ichi Shikata

Hiroyuki Kitabayashi

Kentaro Yoshida

Seiji Nakahata

Keiji Ishibashi

Koji Uematsu

Shinichi Shikata

Takashi Sakurada

Muneyuki Nishioka

Takahiro Imai

Yoshiyuki Yamamoto

Tomohiro Kawase

Takayuki Nishiura

Shin Hashimoto

Katsuhiro Itakura

Daichi Kawaguchi

Satoshi Arakawa

Manabu Okui

Noboru Gotou

Toshiaki Saka

Shin-Ichi Shikata

Affords Group-III nitride single-crystal ingots and III-nitride single-crystal substrates manufactured utilizing the ingots, as well as methods of manufacturing III-nitride single-crystal ingots and methods of manufacturing III-nitride single-crystal substrates, wherein the incidence of cracking during length-extending growth is reduced. Characterized by including a step of etching the edge surface of a base substrate, and a step of epitaxially growing onto the base substrate hexagonal-system III-nitride monocrystal having crystallographic planes on its side surfaces. In order to reduce occurrences of cracking during length-extending growth of the ingot, depositing-out of polycrystal and out-of-plane oriented crystal onto the periphery of the monocrystal must be controlled. A layer of the base substrate edge surface, as just described, where it has been mechanically altered is removed beforehand by etching, whereby crystallographic planes form on the side surfaces of the III-nitride single-crystal ingot that is formed onto the base substrate, which therefore controls depositing-out of polycrystal and out-of-plane oriented crystal and reduces occurrences of cracking.

III-nitride single-crystal ingot, III-nitride single-crystal substrate, method of manufacturing III-nitride single-crystal ingot, and method of manufacturing III-nitride single-crystal substrate

A group III nitride semiconductor crystal substrate has a diameter of at least 25 mm and not more than 160 mm. The resistivity of the group III nitride semiconductor crystal substrate is at least 1&#xd7;10&#x3a9;&#xb7;cm and not more than 0.1 &#x3a9;&#xb7;cm. The resistivity distribution in the diameter direction of the group III nitride semiconductor crystal is at least &#x2212;30% and not more than 30%. The resistivity distribution in the thickness direction of the group III nitride semiconductor crystal is at least &#x2212;16% and not more than 16%.

Group III nitride semiconductor crystal substrate and semiconductor device

Affords a GaN single-crystal mass, a method of its manufacture, and a semiconductor device and method of its manufacture, whereby when the GaN single-crystal mass is being grown, and when the grown GaN single-crystal mass is being processed into a substrate or like form, as well as when an at least single-lamina semiconductor layer is being formed onto a single-crystal GaN mass in substrate form to manufacture semiconductor devices, cracking is controlled to a minimum. The GaN single-crystal masshas a wurtzitic crystalline structure and, at 30&#xb0; C., its elastic constant Cis from 348 GPa to 365 GPa and its elastic constant Cis from 90 GPa to 98 GPa; alternatively its elastic constant Cis from 352 GPa to 362 GPa.

GaN single-crystal mass and method of its manufacture, and semiconductor device and method of its manufacture

There is provided a method for fabricating a gallium nitride crystal with low dislocation density, high crystallinity, and resistance to cracking during polishing of sliced pieces by growing the gallium nitride crystal using a gallium nitride substrate including dislocation-concentrated regions or inverted-polarity regions as a seed crystal substrate. Growing a gallium nitride crystalat a growth temperature higher than 1,100&#xb0; C. and equal to or lower than 1,300&#xb0; C. so as to bury dislocation-concentrated regions or inverted-polarity regionsreduces dislocations inherited from the dislocation-concentrated regions or inverted regions, thus preventing new dislocations from occurring over the dislocation-concentrated regions or inverted-polarity regions. This also increases the crystallinity of the gallium nitride crystaland its resistance to cracking during the polishing.

Method for manufacturing gallium nitride crystal and gallium nitride wafer

An AlGaInN crystal substrate of the present invention has a main plane having an area of at least 10 cm. The main plane has an outer region located within 5 mm from an outer periphery of the main plane, and an inner region corresponding to a region other than the outer region. The inner region has a total dislocation density of at least 1&#xd7;10cmand at most 1&#xd7;10cm. It is thereby possible to provide an AlGaInN crystal substrate having a large size and a suitable dislocation density for serving as a substrate for a semiconductor device, a semiconductor device including the AlGaInN crystal substrate, and a method of manufacturing the same.

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Affords methods of surface treating a substrate and of manufacturing Group III-V compound semiconductors, in which a substrate made of a Group III-V semiconductor compound is rendered stoichiometric, and microscopic roughness on the surface following epitaxial growth is reduced. The methods include preparing a substrate made of a Group III-V semiconductor compound (S), and cleaning the substrate with a cleaning solution whose pH has been adjusted to an acidity of 2 to 6.3 inclusive, and to which an oxidizing agent has been added (S).

Method of surface treating substrates and method of manufacturing III-V compound semiconductors

An AlGaInN substrate in which particles having a grain size of at least 0.2 &#x3bc;m on a surface of the AlGaInN substrate are at most 20 in number when a diameter of the AlGaInN substrate is two inches, and a cleaning method with which the AlGaInN substrate can be obtained are provided. Further, an AlGaInN substrate in which, in a photoelectron spectrum of a surface of the AlGaInN substrate by X-ray photoelectron spectroscopy with a detection angle of 10&#xb0;, a ratio between a peak area of Celectrons and a peak area of Nelectrons (Celectron peak area/Nelectron peak area) is at most 3, and a cleaning method with which the AlGaInN substrate can be obtained are provided. Still further, an AlN substrate in which, in a photoelectron spectrum of a surface of the AlN substrate by X-ray photoelectron spectroscopy with a detection angle of 10&#xb0;, a ratio between a peak area of Alelectrons and a peak area of Nelectrons (Alelectron peak area/Nelectron peak area) is at most 0.65 and a cleaning method with which the AlN substrate can be obtained are provided.

A method for separating chips from a diamond wafer comprising a substrate, a chemically vapor-deposited diamond layer, and microelectronic elements, with the microelectronic elements protected from thermal damage and degradation caused by the thermally decomposed cuttings produced during the processing steps. (1) Front-side grooves are formed on the chemically vapor-deposited diamond layer by laser processing using a laser such as a YAG, CO , or excimer laser each having a large output so that the grooves can have a depth 1/100 to 1.5 times the thickness of the diamond layer. (2) The thermally decomposed cuttings produced during the laser processing are removed by using a plasma. (3) Back-side grooves are formed on the substrate by dicing such that the back-side grooves are in alignment with the front-side grooves . (4) The diamond wafer is divided into individual chips by applying mechanical stresses.

Method for separating chips from diamond wafer

A diamond film is deposited in the thickness of 20 &mgr;m on a silicon wafer 0.8 mm thick by filament CVD. Here the hydrogen content of the diamond film is adjusted in the range of not less than 1% nor more than 5% in atomic percent. By mechanical polishing with a grinding wheel including diamond abrasives, the diamond film is smoothed so that the arithmetic mean roughness (Ra) of the surface thereof becomes not more than 20 nm.

Diamond substrate for surface acoustic wave device, and surface acoustic wave device

The invention offers a hard carbon film and a SAW substrate that are easy to fabricate or low in manufacturing cost while virtually maintaining the quality that affects the important properties of a device that comprises the hard carbon film or the SAW substrate. The hard carbon film comprises a composite film of graphite-like diamond and carbon clusters; the composite film has a continuous crystal structure.

Hard carbon film and surface-acoustic-wave substrate

Hard carbon film and surface acoustic-wave substrate

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

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 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.

Growing community of inventors

Itami, Japan

Tomoki Uemura