Abstract: A semiconductor device having high breakdown withstand voltage includes a first element which is a normally-on type transistor made of nitride compound semiconductor, a second element which is connected to the first element in series and is a transistor having withstand voltage between a source and a drain lower than withstand voltage of the first element, a first diode which is connected between a gate of the first element or a gate of the second element and a drain of the first element so that a cathode of the first diode is connected at the drain's side and has predetermined avalanche withstand voltage, and a first resistance connected to the gate to which the first diode is connected. The avalanche withstand voltage of the first diode is lower than breakdown voltage of the first element.

Abstract: Provided are a nitride-based semiconductor element with reduced leak current, and a manufacturing method thereof. The semiconductor element comprises a substrate; a buffer region that is formed above the substrate; an active layer that is formed on the buffer region; and at least two electrodes that are formed on the active layer. The buffer region includes a plurality of semiconductor layers having different lattice constants, and there is a substantially constant electrostatic capacitance between a bottom surface of the substrate and a top surface of the buffer region when a potential that is less than a potential of the bottom surface of the substrate is applied to the top surface of the buffer region and a voltage between the bottom surface of the substrate and the top surface of the buffer region is changed within a range corresponding to thickness of the buffer region.

Abstract: Provided is a semiconductor device manufacturing method, comprising forming a first sacrificial layer that contacts at least a portion of a first semiconductor layer and has a higher solid solubility for impurities included in the first semiconductor layer than the first semiconductor layer; annealing the first sacrificial layer and the first semiconductor layer; removing the first sacrificial layer through a wet process; after removing the first sacrificial layer, performing at least one of forming an insulating layer that covers at least a portion of the first semiconductor layer and etching a portion of the first semiconductor layer; and forming an electrode layer that is electrically connected to the first semiconductor layer.

Abstract: A method for fabricating a semiconductor device including GaN (gallium nitride) that composes a semiconductor layer and includes forming a gate insulating film, in which at least one film selected from the group of a SiO2 film and an Al2O3 film is formed on a nitride layer containing GaN by using microwave plasma and the formed film is used as at least a part of the gate insulating film.

Abstract: A nitride-based compound semiconductor includes an atom of at least one group-III element selected from the group consisting of Al, Ga, In, and B, a nitrogen atom, and a metal atom that forms a compound by bonding with an interstitial atom of the at least one group-III element. The metal atom is preferably iron or nickel. A doping concentration of the metal atom is preferably equal to a concentration of the interstitial atom of the at least one group-III element.

Abstract: Provided is a semiconductor device comprising a back barrier layer that is formed by a group III-V compound semiconductor above a substrate; a channel layer that is formed of a group III-V compound semiconductor having less bandgap energy than the back barrier layer, is formed on the back barrier layer, and includes a recessed portion formed in at least a portion of the channel layer above the back barrier layer to be thinner than other portions of the channel layer; a first electrode that is in ohmic contact with the channel layer; and a second electrode formed at least above the recessed portion of the channel layer.

Abstract: Solid, shaped and fired fibers of Ti4O7 and Ti5O9 are made by firing TiO2 fibers in a reducing atmosphere. In a first aspect, the TiO2 fibers are made by extruding into air a viscous TiO2 gel and heat treating the resulting green fibers to remove solvent, decompose and to volatilize undesired constituents to form electrically conductive, refractory fibers of Ti4O7 and Ti5O9. In a second aspect, solid, shaped and fired fibers of Ti4O7 and Ti5O9 are made by firing extruded fibers from mixtures of TiO2.

Abstract: Solid, shaped and fired fibers of Ti4O7 and Ti5O9 are made by firing TiO2 fibers in a reducing atmosphere. In a first aspect, the TiO2 fibers are made by extruding into air a viscous TiO2 gel and heat treating the resulting green fibers to remove solvent, decompose and to volatilize undesired constituents to form electrically conductive, refractory fibers of Ti4O7 and Ti5O9. In a second aspect, solid, shaped and fired fibers of Ti4O7 and Ti5O9 are made by firing extruded fibers from mixtures of TiO2.

Abstract: A vertical semiconductor rectifier device includes a semiconductor substrate of first conductivity type and having a plurality of gates insulatively formed on a first major surface and a plurality of source/drain regions of the first conductivity type formed in surface regions of second conductivity type in the first major surface adjacent to the gates. A plurality of channels of the second conductivity type each abuts a source/drain region and extends under a gate, each channel being laterally graded with a sloped P-N junction sepcarating the channel region from the substrate of first conductivity type, In fabricating the vertical semiconductor rectifier device, a partial ion mask is formed on the surface of the semiconductor with the mask having a sloped surface which varies the path length of ions through the mask to form laterally-graded channel regions.

Abstract: A vertical semiconductor rectifier device includes a semiconductor substrate of first conductivity type and having a plurality of gates insulatively formed on a first major surface and a plurality of source/drain regions of the first conductivity type formed in surface regions of second conductivity type in the first major surface adjacent to the gates. A plurality of channels of the second conductivity type each abuts a source/drain region and extends under a gate, each channel being laterally graded with a sloped P-N junction separating the channel region from the substrate of first conductivity type. In fabricating the vertical semiconductor rectifier device, a partial ion mask is formed on the surface of the semiconductor with the mask having a sloped surface which varies the path length of ions through the mask to form laterally-graded channel regions.

Abstract: The performance of electrochemical energy devices such as batteries, fuel cells, capacitors and sensors is enhanced by the use of electrically conducting ceramic materials in the form of fibers, powder, chips and substrates.

Abstract: A vertical semiconductor rectifier device includes a semiconductor substrate of first conductivity type and having a plurality of gates insulatively formed on a first major surface and a plurality of source/drain regions of the first conductivity type formed in surface regions of second conductivity type in the first major surface adjacent to the gates. A plurality of channels of the second conductivity type each abuts a source/drain region and extends under a gate, each channel being laterally graded with a sloped P-N junction separating the channel region from the substrate of first conductivity type. In fabricating the vertical semiconductor rectifier device, a partial ion mask is formed on the surface of the semiconductor with the mask having a sloped surface which varies the path length of ions through the mask to form laterally-graded channel regions.

Abstract: A Schottky diode comprises a semiconductor body of one conductivity type, the semiconductor body having a grooved surface, a metal layer on the grooved surface and forming a Schottky junction with sidewalls of the grooved surface and ohmic contacts with top portions of the grooved surface. The semiconductor body preferably includes a silicon substrate with the grooved surface being on a device region defined by a guard ring of a conductivity type opposite to the conductivity type of the semiconductor body, and a plurality of doped regions at the bottom of grooves and forming P-N junctions with the semiconductor body. The P-N junctions of the doped regions form carrier depletion regions across and spaced from the grooves to increase the reverse bias breakdown voltage and reduce the reverse bias leakage current. The ohmic contacts of the metal layer increase forward current and reduce forward voltage of the Schottky diode.

Abstract: A power rectifier having low on resistance, mass recovery times and low forward voltage drop. In a preferred embodiment, the present invention provides a power rectifier device employing a vertical device structure, i.e., with current flow between the major surfaces of the discrete device. The device employs a large number of parallel connected cells, each comprising a MOSFET structure with a gate to drain short via a common metallization. This provides a low Vf path through the channel regions of the MOSFET cells to the source region on the other side of the integrated circuit. A thin gate structure is formed annularly around the pedestal regions on the upper surface of the device and a precisely controlled body implant defines the channel region and allows controllable device characteristics, including gate threshold voltage and Vf. A parallel Schottky diode is also provided which increases the switching speed of the MOSFET cells.

Abstract: A power rectifier having low on resistance, fast recovery times and very low forward voltage drop. In a preferred embodiment, the present invention provides a power rectifier device employing a vertical device structure, i.e., with current flow between the major surfaces of the discrete device. The device employs a large number of parallel connected cells, each comprising a MOSFET structure with a gate to drain short via a common metallization. A self aligned body implant and a shallow silicide drain contact region integrated with a metal silicide drain contact define a narrow channel region and allow very high cell density. This provides a low Vf path through the channel regions of the MOSFET cells to the contact on the other side of the integrated circuit. The present invention further provides a method for manufacturing a rectifier device which provides the above desirable device characteristics in a repeatable manner. Also, only two masking steps are required, reducing processing costs.

Abstract: The invention concerns a lead-acid battery having all the surfaces of all the electrodes under high pressure and their circumferences kept unchanged by support from mechanically rigid cell walls such that only the thickness of the electrodes is allowed to expand under strong resilient load during the discharge and return during charge. The pressure is 0.49-10.sup.5 -9.81-10.sup.5 Pa (0.5-10 kp/cm.sup.2), and may be obtained by separators or by springs applied to the outer sides of the cell container and may be changed for increased or decreased capacity. The construction of the tubular battery design, prevents material losses due to sludging and a long working life is obtained, since also a totally corroded lead conductor under high pressure may function as a current conductor. The rigid outer containers also allow high liquid pressure and thus a high oxygen solubility and oxygen recombination for sealed cells.