Abstract: A method of fabricating a MOSEFT device, which is suitable for fabricating an III-V group semiconductor device. A substrate comprises a buffer layer and a channel layer, wherein silicon oxide is formed on the channel layer by a liquid phase deposition method (LPD) to control the parameters of growth solution. A silicon oxide insulating layer that is formed on the channel layer has a thickness of approximately 40 Å, wherein the silicon oxide insulating layer is used as a gate oxide layer. A source, a drain and a gate are formed on the gate oxide layer. The LPD process is performed in a temperature range from room temperature to 60° C. Thus, the low temperature of the LPD technique will not lead to a negative heat effect on other fabrications or on the wafer, therefore the low temperature will not cause thermal stress, dopant redistribution, dopant diffusion or material interaction, for example.

Abstract: Methods are provided for producing a compound semiconductor substrate including: a mica substrate; and a III-V group compound semiconductor layer containing nitrogen as its main component grown on the mica substrate.

Abstract: A semiconductor device includes a compound semiconductor substrate having a resistivity less than 1.0×108 Ohm-cm at least at one surface thereof, a buffer layer formed on the compound semiconductor substrate and having a super lattice structure, and an active layer formed on the buffer layer and having an active element formed therein.

Abstract: A single electron transistor using porous silicon, which is fabricated by applying porous silicon having a size of several tens of nanometers obtained by electrochemically etching silicon, and a fabrication method thereof, are provided. In the single electron transistor using porous silicon, silicon pores, each of which has a diameter of 5 nm or less, are fabricated by electrochemically etching a silicon on insulator (SOI) substrate having silicon dioxide (SiO2) in its lower portion using an HF-based solution, and serve as islands of a single electron transistor. Also, a source and a drain are formed of silicon on which metal is deposited or silicon doped with impurities. Hence, formation of islands and tunnel barriers is easy, mass production is possible, and the sizes of islands can be controlled by oxidation, so that single electron transistors capable of operating at room temperature can be easily fabricated.

Abstract: First, a polysilicon film is formed on a gate oxide film. Next, a polysilicon oxide film is formed on the polysilicon film. Thereafter, the polysilicon film is thermally treated to allow a crystal grain in the polysilicon film to grow from the gate oxide film and the polysilicon oxide film. In a MOS type semiconductor device manufactured in this manner has a gate electrode formed of a plurality of laminated polycrystalline silicon layers each having substantially a single crystal grain in a thickness direction of the gate electrode.

Abstract: A semiconductor device operable with a single positive power source, enabling an increase in efficiency, and improved in high-frequency characteristics by lowering the resistivity of a gate contact, including a carrier run layer formed on a substrate for running of carriers; a carrier supply layer formed on the carrier run layer, having a larger bandgap than the carrier run layer, and containing a first conductivity type impurity; a barrier layer formed on the carrier supply layer and having a smaller bandgap than the carrier supply layer; a source electrode and a drain electrode formed on the barrier layer at a predetermined distance from each other; a gate electrode formed on the barrier layer between the source electrode and the drain electrode away from the source electrode and the drain electrode; and a first low resistivity region formed at least below the gate electrode in the barrier layer and containing a second conductivity type impurity opposite in conductivity to the first conductivity type, and a

Abstract: The semiconductor light emitting element of the present invention includes: a compound semiconductor substrate having a first conductivity type; a light emitting layer; a compound semiconductor interface layer having a second conductivity type and not containing Al; and a current diffusion layer having the second conductivity type and being made of a compound semiconductor not containing Al.

Abstract: A method for manufacturing a SiC device embraces (a) depositing a polysilicon film above a SiC substrate; (b) delineating the polysilicon film into required pattern; and (c) annealing the SiC substrate in a water rich ambient to selectively grow a thick localized thermal oxide film above the SiC substrate. At the surface of SiC substrate, source/drain regions and substrate contact region are formed. In the water rich ambient, the H2O partial pressure is so maintained that it is more than 0.95.

Abstract: A semiconductor substrate, a field effect transistor, a method of forming a SiGe layer and a method of forming a strained Si layer using the same, and a method of manufacturing a field effect transistor are provided, which enable the threading dislocation density of the SiGe layer to be reduced and the surface roughness to be minimized. On top of a Si substrate 1 is provided a SiGe buffer layer 2, 12 constructed of a plurality of laminated layers comprising alternating layers of a SiGe gradient composition layer 2a, 12a in which the Ge composition ratio increases gradually from the Ge composition ratio of the base material, and a SiGe constant composition layer 2b, 12b which is provided on top of the gradient composition layer and in which the Ge composition ratio is equal to that of the upper surface of the gradient composition layer.

Abstract: A high voltage microwave field effect transistor (FET) and method for its manufacture. The FET (10) includes a channel layer (18) formed of compressively strained GaInP. Carrier confinement layers (16), (20) formed of tensile strained (AlGa)InP are formed both above (20) and below (16) the channel layer (20) to confine the carriers to the channel layer (20) and to provide a high breakdown voltage.

Abstract: A process of supplying moisture at low flow rates which permits high precision control of the flow of moisture to a semiconductor manufacturing line from an apparatus for the generation of moisture, characterized in that the flow of hydrogen to a moisture-generating reactor is controlled by means of a flow controller in such a way that an amount of hydrogen as fed is gradually increased from the start and reaches a specific set level such that when a specific time has passed, a predetermined rate of moisture begins to be produced and supplied to the semiconductor manufacturing line. The moisture is generated in the apparatus for generation of moisture in which hydrogen and oxygen are (a) fed into a reactor provided with a coat of platinum on the wall in the interior space, (b) enhanced in reactivity by the platinum catalytic action, and (c) caused to instantaneously react with each other at a temperature lower than the ignition point to produce moisture without undergoing combustion at a high temperature.

Abstract: There are provided a GaN field effect transistor (FET) exhibiting an excellent breakdown voltage owing to the high quality of GaN crystal in a region where the electric lines of force concentrate during operation of the same, and a method of manufacturing the same. The FET has a layer structure formed of a plurality of GaN epitaxial layers. A gate electrode and a source electrode are disposed on the surface of the layer structure, and a drain electrode is disposed on the reverse surface of the same. A region of the layer structure in which the electric lines of force concentrate during operation of the FET has a reduced dislocation density compared with the other regions in the layer structure.

Abstract: When a device using GaN semiconductors is made on a hard and chemically stable single-crystal substrate such as sapphire substrate or SiC substrate, a semiconductor device and its manufacturing method ensure high-power output or high-frequency operation of the device by thinning the substrate or making a via hole in the substrate. When a light emitting device using GaN semiconductors is made on a non-conductive single-crystal substrate such as sapphire substrate, the semiconductor device and its manufacturing method reduce the operation voltage of the light emitting device by making a via hole to the substrate. More specifically, after making a GaN FET by growing GaN semiconductor layers on the surface of a sapphire substrate, the bottom surface of the sapphire substrate is processed by lapping, using an abrasive liquid containing a diamond granular abrasive material and reducing the grain size of the abrasive material in some steps, to reduce the thickness of the sapphire substrate to 100 &mgr;m or less.

Abstract: The present invention provides a structure of a semiconductor device, the structure comprising: a compound semiconductor multi-layer structure having at least a channel region; and at least an ohmic contact layer provided adjacent to a first side face of the multi-layer structure, and the ohmic contact layer being in contact with at least a part of the first side face, wherein the ohmic contact layer has a top extending portion which extends in contact with a part of a top surface of the multi-layer structure.

Abstract: A process of forming a high-resistance GaN crystal layer which is useful in producing a GaN FET. The high-resistance GaN crystal layer is formed by doping a GaN crystal with one or more acceptor-type impurities selected from the group consisting of C, Mg and Zn during epitaxial growth thereof. Specifically, during the epitaxial growth of the GaN crystal, the GaN crystal is doped with Mg or Zn in an atmosphere of hydrogen at a temperature of 600° C. or higher, or the GaN crystal is doped with Mg or Zn at a concentration of 1×1017 cm−3 or higher and then is doped with C at a concentration of 1×1018 cm−3 or higher. The GaN layer may be ion-implanted with an acceptor such as C, Mg or Zn or with a donor such as Si, to control the carrier density and thus the threshold value.

Abstract: To improve crystallographic property of a nitride III-V compound semiconductor layer grown on a sapphire substrate, a plurality of recesses are made on a major surface of the sapphire substrate, and the nitride III-V compound semiconductor layer is grown thereon. At least a part of the inner surface of each recess makes an angle not less than 10 degrees with respect to the major surface of the sapphire substrate. The recesses are buried with nitride III-V compound semiconductor crystal having a higher Al composition ratio than the nitride III-V compound semiconductor layer, such as AlxGa1−xN crystal whose Al composition ratio x is 0.2 or more, for example. Each recess has a depth not less than 25 nm and a width not less than 30 nm. The recesses may be made either upon thermal cleaning of the sapphire substrate or by using lithography and etching, thermal etching, or the like.

Abstract: A semiconductor device is a hetero-junction bipolar transistor structured by having a gallium arsenide film among laminated films, which has an indium gallium phosphide (InGaP) film which is connected to the gallium arsenide film and functions as an emitter, wherein the indium gallium phosphide film includes antimony (Sb). By including antimony, a carrier density can be deterred from decreasing near an interface between the gallium arsenide film and the indium gallium phosphide film and an emitter resistance can be reduced to a minimum.

Abstract: A method for growing high-quality gallium nitride over a substrate is disclosed. The method comprises growing first layer with a high dislocation density over the substrate, a second layer having a high number of point defects and a reduced dislocation density as compared to the dislocation density of the first layer over the first layer, and a third layer having a reduced number of point defects as compared to the second layer over the second layer. The resulting gallium nitride is semi-insulating, which inhibits parasitic current flow and parasitic capacitive effects, yet it not so insulating that electron flow in adjacent transistor channels is inhibited.

Abstract: A method which includes, prior to depositing the encapsulating silicon layer: A) depositing on the Si1−xGex layer a thin film of amorphous or polycrystalline silicon, then in treating said silicon film with gas nitric oxide at a temperature between 450 to 600° C. and at a pressure level of 104 to 105 Pa to obtain a thin nitrided silicon film; or B) depositing on the Si1−xGex layer a thin film of amorphous or polycrystalline silicon and oxidizing the silicon film to form a surface film of silicon oxide less than 1 nm thick and optionally treating the oxidized amorphous or polycrystalline silicon film with nitric oxide as in A). The invention is applicable to CMOS semiconductors.

Abstract: An isolation trench is formed from a first isolation trench in an integrated circuit substrate between active regions in the integrated circuit substrate. An insulating layer is formed in the first isolation trench, wherein the insulating layer includes a portion that protrudes from the first isolation trench. A second isolation trench is formed on the first isolation trench and self-aligned to the active regions in the integrated circuit substrate, wherein the second isolation trench includes the protruding portion of the insulating layer. By forming the isolation trench in two steps, the isolation trench may be formed to the appropriate depth without developing a seam in the insulating layer. In particular, the first isolation trench is formed to a depth and filled with the insulating layer which protrudes from the trench. The second isolation trench is built up around the protruding insulating layer to provide the total depth for adequate isolation of the active areas.

Abstract: A normally-off semiconductor device with gate regions formed in a high-quality base is manufactured by forming a P.sup.+ layer in a lower surface of an N.sup.- substrate, selectively forming P.sup.+ gate regions in an upper surface of the N.sup.- substrate, forming intergate P.sup.+ regions in the upper surface of the N.sup.- substrate between the P.sup.+ gate regions, forming an N.sup.+ layer in an upper surface of an N.sup.- substrate, joining the N.sup.- substrate and the N.sup.- substrate to each other by heating them at about 800.degree. C. in a hydrogen atmosphere while the upper surface of the N.sup.- substrate and a lower surface of the N.sup.- substrate are being held against each other, and forming an anode electrode and a cathode electrode.

Abstract: A gate quality oxide-compound semiconductor structure (10) is formed by the steps of providing a III-V compound semiconductor wafer structure (13) with an atomically ordered and chemically clean semiconductor surface in an ultra high vacuum (UHV) system (20), directing a molecular beam (26) of gallium oxide onto the surface of the wafer structure to initiate the oxide deposition, and providing a second beam (28) of atomic oxygen to form a Ga.sub.2 O.sub.3 layer (14) with low defect density on the surface of the wafer structure. The second beam of atomic oxygen is supplied upon completion of the first 1-2 monolayers of Ga.sub.2 O.sub.3. The molecular beam of gallium oxide is provided by thermal evaporation from a crystalline Ga.sub.2 O.sub.3 or gallate source, and the atomic beam of oxygen is provided by either RF or microwave plasma discharge, thermal dissociation, or a neutral electron stimulated desorption atom source.

Abstract: A manufacturing method of a junction field effect transistor, promising a low ON resistance, high maximum drain current and linearity with a high transmission gain and also enabling the gate length to be reduced, makes a channel layer by sequentially epitaxially growing an undoped GaAs layer, n.sup.+ -type GaAs layer and n-type GaAs layer on a semi-insulating GaAs substrate via a GaAs buffer layer. Through an opening formed in a diffusion mask in form of a SiN.sub.x film on the n-type GaAs layer, Zn is diffused into the n-type GaAs layer to form a p.sup.+ -type gate region. From above the diffusion mask, a gate metal layer is deposited, and patterned to make a gate electrode in the opening of the diffusion mask in self-alignment with the p.sup.+ -type gate region.

Abstract: A method for forming conductive lines such as interconnects and DRAM gate stacks. A blanket stack is formed on a substrate including a conductive diffusion barrier, a near noble metal such as cobalt, followed by a silicon layer and a top insulator layer. The blanket stack is patterned with resist to define the conductive lines. The stack is dry etched down to the near noble metal layer. The resist is then removed and the stack is annealed to react the near noble metal and silicon to form a conductive compound having fine grain size. The unreacted noble metal is then wet etched, using the conductive diffusion barrier as a wet etch stop. A further dry etch is then performed down to the substrate, using the top insulator layer as a mask. In this manner, only one mask is required to form the conductive line.

Abstract: A method of fabricating a gate quality oxide-compound semiconductor structure includes forming an insulating Ga.sub.2 O.sub.3 layer on the surface of a compound semiconductor wafer structure by a supersonic gas jet containing gallium oxide molecules and oxygen. In a preferred embodiment, a III-V compound semiconductor wafer structure with an atomically ordered and chemically clean semiconductor surface is transferred from a semiconductor growth chamber into an insulator deposition chamber via an ultra high vacuum preparation chamber. Ga.sub.2 O.sub.3 deposition onto the surface of the wafer structure is initiated by a supersonic gas jet pulse and proceeds via optimization of pulse duration, speed of gas jet, mole fraction of gallium oxide molecules and oxygen atoms, and plasma energy.

Abstract: The present invention is directed to a silicon carbide field effect transistor. The FET is formed on a silicon carbide monocrystalline substrate. An insulative material gate having a pair of spaced apart sidewalls is patterned on the substrate. The insulative material comprises a first insulation material overlayed by an electrically conductive layer. Within the substrate is lightly doped base regions located partially under the sidewalls of the gate and extending into the exposed substrate. Associated with the lightly doped base regions are heavily doped source regions aligned with the exposed substrate. On the underside of the substrate is a drain region to form the FET. Further in accordance with the present invention, a method to fabricate a field effect transistor is disclosed. The transistor is formed in a monocrystalline substrate of silicon carbide. Forming a transistor on the silicon carbide substrate entails depositing a first electrically insulative layer over the substrate.

Abstract: A method of defining a line width includes forming a spacer (45) over a layer (42) and using the spacer (45) as an etch mask (57) while etching the layer (42). In this manner, a width (47) of the spacer (45) is used to define a width or line width (47) for the layer (42). Another method of using a spacer to define a line width includes forming a spacer (14) over a substrate (11), depositing a layer (15) over the substrate (11) and the spacer (14), planarizing the layer (15) to expose the spacer (14), and removing the spacer (14) to form an opening (19) over the substrate (11), wherein the opening (19) has a width or line width (17) of the spacer (14).