Abstract: There is provided a semiconductor device including: a SiC substrate; an AlGaN layer formed on the SiC substrate; a source electrode and a drain electrode formed on the AlGaN layer so as to be spaced from each other; a first insulation film formed between the source electrode and the drain electrode and having a band-like opening parallel to the drain electrode and the source electrode; a gate electrode formed at the opening in the first insulation film; a second insulation film formed on the first insulation film in such a manner as to cover a surface of the gate electrode; and a source field plate electrode which is formed on the second insulation film and the source electrode and an end portion of which on the drain electrode side is spaced from the second insulation film, thereby suppressing degradation in device performance.

Abstract: A method of making a semiconductor device includes forming a p-type semiconductor region to an n-type semiconductor substrate in such a manner that the p-type semiconductor region is partially exposed to a top surface of the semiconductor substrate, forming a Schottky electrode of a first material in such a manner that the Schottky electrode is in Schottky contact with an n-type semiconductor region exposed to the top surface of the semiconductor substrate, and forming an ohmic electrode of a second material different from the first material in such a manner that the ohmic electrode is in ohmic contact with the exposed p-type semiconductor region. The Schottky electrode is formed earlier than the ohmic electrode.

Abstract: Devices and methods for providing JFET transistors with improved operating characteristics are provided. Specifically, one or more embodiments of the present invention relate to JFET transistors with a higher diode turn-on voltage. For example, one or more embodiments include a JFET with a doped silicon-carbide gate, while other embodiments include a JFET with a metal gate. One or more embodiments also relate to systems and devices in which the improved JFET may be employed, as well as methods of manufacturing the improved JFET.

Abstract: A unit cell of a metal-semiconductor field-effect transistor (MESFET) is provided. The MESFET has a source, a drain and a gate. The gate is between the source and the drain and on an n-type conductivity channel layer. A p-type conductivity region is provided beneath the gate between the source and the drain. The p-type conductivity region is spaced apart from the n-type conductivity channel layer and electrically coupled to the gate. Related methods are also provided herein.

Abstract: A J-FET includes a channel layer of a first conductivity type (a Si-doped n-type AlGaAs electron supply layers 3 and 7, undoped AlGaAs spacer layers 4 and 6, and an undoped InGaAs 5 channel layer 5) formed above a semi-insulating GaAs substrate, an upper semiconductor layer made up of at least one semiconductor layer and formed above the channel layer of the first conductivity type, a semiconductor layer of a second conductivity type (C-doped p+-GaAs layer 18) formed in a recess made in the upper semiconductor layer or formed above the upper semiconductor layer, a gate electrode placed above and in contact with the semiconductor layer of the second conductivity type, and a gate insulating film including a nitride film formed above and in contact with the upper semiconductor layer and an oxide film formed above the nitride film and having a larger thickness than the nitride film.

Abstract: A multilayer structure including a first electron supply layer and a second electron supply layer is used for an electron supply layer. A multilayer structure including an SiN film and an SiO2 film is used for an insulating film to be formed on the surface of a semiconductor. In forming an opening for exposing the electron supply layer in the insulating film, the SiN film that is in contact with the semiconductor is side-etched. Accordingly, it is possible to avoid a contact between a gate electrode and a portion, which is located on the side of the electron supply layer, of the inner peripheral surface of the opening, and further to expose only the second electron supply layer in the vicinity of the gate electrode.

Abstract: A Schottky electrode including a WNx layer on an n-type GaN layer. A crystal plane of the n-type GaN layer is in contact with a crystal plane of the WNx layer. The crystal plane of the n-type GaN layer is a (0001)-plane, and the crystal plane of the WNx layer is (111)-oriented. The WNx layer may be an electrode layer having an NaCl-type structure including at least one metal selected from the group consisting of zirconium, hafnium, niobium, tantalum, molybdenum and tungsten, and at least one element selected from nitrogen and carbon. Further, the lattice constant of the electrode layer is preferably 0.95 to 1.05 times the a-axis lattice constant of the n-type GaN layer, multiplied by 2(1/2).

Abstract: A semiconductor device which can prevent peeling off of a gate electrode is provided. The semiconductor device has GaN buffer layer formed on substrate 11, undoped AlGaN layer 13 formed on this buffer layer 12, drain electrode 16 and source electrode 17 formed separately on undoped AlGaN layer 13, which form ohmic junctions with undoped AlGaN layer 13. Between drain electrode 16 and source electrode 17, insulating layer 20 which has opening 19 is formed, and metal film is formed on a surface of insulating layer 2. Gate electrode 18 which forms a Schottky barrier junction with undoped AlGaN layer 13 is formed in opening 19, and gate electrode 18 adheres to metal film 21.

Abstract: Reduced leakage current field-effect transistors and fabrication methods. Semiconductor device including substrate of first conductivity type, first well and second well of second conductivity type in substrate, channel of second conductivity type between first well and second well in substrate, and gate region of first conductivity type within channel, wherein gate region is electrically operable to modulate depletion width of channel. First well may be a drain region and the second well may be a source region. Channel includes first link region between gate region and first well or drain region and second link region between the gate region and second well or source region; wherein first link region is of second conductivity type of at least two doping densities. First link region is higher doped in a portion adjacent to drain region than in another portion adjacent to gate region. Method of fabricating a reduced leakage current FET.

Abstract: Affords Group III nitride semiconductor devices in which the leakage current from the Schottky electrode can be reduced. In a high electron mobility transistor 11, a supporting substrate 13 is composed of AlN, AlGaN, or GaN, specifically. An AlYGa1?YN epitaxial layer 15 has a full-width-at-half maximum of (0002) plane XRD of 150 sec or less. A GaN epitaxial layer 17 is provided between the gallium nitride supporting substrate and the AlYGa1?YN epitaxial layer (O<Y?1). A Schottky electrode 19 is provided on the AlYGa1?YN epitaxial layer 15. The Schottky electrode 19 constitutes a gate electrode of the high electron mobility transistor 11. The source electrode 21 is provided on the gallium nitride epitaxial layer 15. The drain electrode 23 is provided on the gallium nitride epitaxial layer 15.

Abstract: A semiconductor device and a fabrication method of the semiconductor device, the semiconductor device including: a gate electrode, a source electrode, and a drain electrode which are placed on a first surface of a substrate, and have a plurality of fingers; a gate terminal electrode, a source terminal electrode, and the drain terminal electrode which governed and formed a plurality of fingers for every the gate electrode, the source electrode, and the drain electrode; an active area placed on an underneath part of the gate electrode, the source electrode, and the drain electrode, on the substrate between the gate electrode and source electrode, and on the substrate between the gate electrode and the drain electrode; a sealing layer which is placed on the active area, the gate electrode, the source electrode, and the drain electrode through a cavity part, and performs a hermetic seal of the active area, the gate electrode, the source electrode, and the drain electrode.

Abstract: A semiconductor device has a semiconductor (e.g., a silicon substrate), an electrically conductive region (e.g., a source region and a drain region) which is in contact with the semiconductor to form a Schottky junction, and an insulator. The insulator is in contact with the semiconductor and the electrically conductive region, and has a fixed-charge containing region which contains a fixed charge and extends across a boundary between the semiconductor and the electrically conductive region.

Abstract: A semiconductor device includes: a semiconductor substrate; a diode having a cathode formed on a first surface side of the semiconductor substrate and an anode formed on a second surface side of the semiconductor substrate; and a transistor formed over the semiconductor substrate. The transistor includes a semiconductor layer laminate formed over the semiconductor substrate, a source electrode and a drain electrode that are formed spaced apart from each other over the semiconductor layer laminate, and a gate electrode formed between the source electrode and the drain electrode. The source electrode is electrically connected to the anode, and the drain electrode is electrically connected to the cathode.

Abstract: The present invention provides a bi-directional field effect transistor and a matrix converter using the same, in which a current flowing bi-directionally can be controlled by means of a single device. The bi-directional field effect transistor includes: a semiconductor substrate 1; a gate region which is arranged on the semiconductor substrate 1, with a channel parallel to a principal surface of the substrate 1 and a gate electrode 13a for controlling conductance of the channel; a first region which is arranged on a first side of the channel; and a second region which is arranged on a second side of the channel; wherein a forward current which flows from a first electrode 11a of the first region through the channel to a second electrode 12a of the second region and a backward current which flows from the second electrode 12a through the channel to the first electrode 11a can be controlled by a gate voltage applied to the gate electrode 13a.

Abstract: Provided are a semiconductor device with a T-gate electrode capable of improving stability and a high frequency characteristic of the semiconductor device by reducing source resistance, parasitic capacitance, and gate resistance and a method of fabricating the same. In the semiconductor device, in order to form source and drain electrodes and the T-gate electrode on a substrate, first and second protective layers constructed with silicon oxide layers or silicon nitride layers are formed on sides of a supporting part under a head part of the T-gate electrode, and the second protective layer constructed with a silicon oxide layer or silicon nitride layer is formed on sides of the source and drain electrodes. Accordingly, it is possible to protect an activated region of the semiconductor device and reduce gate-drain parasitic capacitance and gate-source parasitic capacitance.

Abstract: A field-effect transistor includes a carrier transport layer made of nitride semiconductor, a gate electrode having first and second sidewall surfaces on first and second sides, respectively, an insulating film formed directly on the gate electrode to cover at least one of the first and second sidewall surfaces, first and second ohmic electrodes formed on the first and second sides, respectively, a passivation film including a first portion extending from the first ohmic electrode toward the gate electrode to cover a surface area between the first ohmic electrode and the gate electrode and a second portion extending from the second ohmic electrode toward the gate electrode to cover a surface area between the second ohmic electrode and the gate electrode, wherein the insulating film is in direct contact with at least the first and second passivation film portions, and has a composition different from that of the passivation film.

Abstract: This invention proposes the use of a thermodynamic screen placed under the electronic devices whose excess noise is to be reduced in order to block the transverse currents between said devices and subjacent layers that are responsible for the aforementioned excess noise. For epitaxial layers as those used in Microelectronics, the barrier layer (2) with an opposed doping to the epilayer supporting the devices (4), and the non-doped separating layer (3) form the thermodynamic screen which, embedded between the epilayer (4) and the substrate (1), reduces the aforementioned transverse currents and thus the excess noise of the devices on the epilayer (4) when they are biased.

Abstract: A semiconductor device including a schottky device and a trench type semiconductor switching device such as a MOSFET formed in a common die.

Abstract: A field effect device includes at least one segmented field plate, each of the at least one segmented field plates having a plurality of segments that each form a plate of a capacitor, wherein the field effect device is connected to an electronic element that dynamically connects selected segments to selectively set a gate-to-drain and a drain-to-source capacitance. An ultrasonic device includes a transducer coupled to a switching device that switches the transducer between a transmit mode and a receive mode switching device, wherein the switching device includes the field effect device.

Abstract: A MESFET and method for fabricating a MESFET are provided. The method includes forming an n-type channel portion in a substrate and forming a p-type channel portion in the substrate. A boundary of the n-type channel portion and a boundary of the p-type channel portion define an intrinsic region in the substrate.

Abstract: In a semiconductor device, a SiN first protective insulating film is formed on a semiconductor layer. A T-shaped gate electrode is formed on the semiconductor layer. A SiN second protective insulating film spreads in an umbrella shape from above the T-shaped gate electrode. A hollow region is formed between the two SiN films. The SiN films are coated with a SiN third protective insulating film with the hollow region remaining.

Abstract: A semiconductor device for high frequency includes a channel region fabricated on a compound semiconductor substrate, a gate electrode fabricated on the channel region, a source electrode and a drain electrode alternately fabricated on the channel region by sandwiching the gate electrode, a bonding pad to be connected to an external circuit, and an air-bridge having one end connected to the source electrode or the drain electrode above and outside the channel region, and the other end connected to the bonding pad.

Abstract: A transistor includes a nitride semiconductor layer and a gate electrode layer. The gate electrode layer includes a tantalum nitride layer being formed on the nitride semiconductor layer. The tantalum nitride layer forms a Schottky junction with the nitride semiconductor layer. The transistor also includes an insulating film formed on the nitride semiconductor layer. The insulating film surrounds the gate electrode layer. The portion of the gate electrode layer in contact with the nitride semiconductor layer has a higher nitrogen mole fraction than the other portion of the gate electrode layer.

Abstract: A composite contact for a semiconductor device is provided. The composite contact includes a DC conducting electrode that is attached to a semiconductor layer in the device, and a capacitive electrode that is partially over the DC conducting electrode and extends beyond the DC conducting electrode. The composite contact provides a combined resistive-capacitive coupling to the semiconductor layer. As a result, a contact impedance is reduced when the corresponding semiconductor device is operated at high frequencies.

Abstract: A rectifier MESFET includes an N-channel MESFET having its gate connected to its source, and at the same current density having a voltage drop lower than the gate Schottky diode. A Schottky diode may be connected in parallel with the N-channel device to provide over current protection. A Zener may also be connected in parallel to provide reverse voltage protection. A second N-channel device may be connected in parallel. The addition of the second N-channel provides two different operational mode: synchronous rectification where the majority of current flows through the low resistance first N-channel device and asynchronous rectification where the majority of current flows through the somewhat higher resistance first N-channel device.

Abstract: A semiconductor device has a Group III nitride semiconductor layer and a gate electrode formed on the Group III nitride semiconductor layer. The gate electrode contains an adhesion enhancing element. A thermally oxidized insulating film is interposed between the Group III nitride semiconductor layer and the gate electrode.

Abstract: The present invention provides a Schottky electrode for a nitride semiconductor device having a high barrier height, a low leak current performance and a low resistance and being thermally stable, and a process for production thereof. The Schottky electrode for a nitride semiconductor has a layered structure that comprises a copper (Cu) layer being in contact with the nitride semiconductor and a first electrode material layer formed on the copper (Cu) layer as an upper layer. As the first electrode material, a metal material which has a thermal expansion coefficient smaller than the thermal expansion coefficient of copper (Cu) and starts to undergo a solid phase reaction with copper (Cu) at a temperature of 400° C. or higher is employed.

Abstract: Field effect transistor devices comprising III-V semiconductors and organic gate dielectric materials, such dielectric materials as can afford flexibility in device design and fabrication.

Abstract: A LDMOS transistor having a gate shield provides reduced drain coupling to the gate shield and source by restricting the thickness of the gate shield and by confining a source contact to the source region without overlap of the gate.

Abstract: A field-effect transistor which comprises a buffer layer and a barrier layer each of which is made of a Group III nitride compound semiconductor and has a channel at the interface inside of the buffer layer to the barrier layer, wherein the barrier layer has multiple-layer structure comprising an abruct interface providing layer which composes the lowest semiconductor layer in said barrier layer and whose composition varies rapidly at the interface of said buffer layer, and an electrode connection plane providing layer which constructs the uppermost semiconductor layer and whose upper surface is formed flat.