50 results about "Schottky gate" patented technology

A GaN semiconductor device with improved heat resistance of the Schottky junction electrode and excellent power performance and reliability is provided. In this semiconductor device having a Schottky gate electrode 17 which is in contact with an AlGaN electron supplying layer 14, a gate electrode 17 comprises a laminated structure wherein a first metal layer 171 formed of any of Ni, Pt and Pd, a second metal layer 172 formed of any of Mo, Pt, W, Ti, Ta, MoSi, PtSi, WSi, TiSi, TaSi, MoN, WN, TiN and TaN, and a third metal layer formed of any of Au, Cu, Al and Pt. Since the second metal layer comprises a metal material having a high melting point, it works as a barrier to the interdiffusion between the first metal layer and the third metal layer, and the deterioration of the gate characteristics caused by high temperature operation is suppressed. Since the first metal layer contacting the AlGaN electron supplying layer 14 has a high work function, the Schottky barrier is high, and superior Schottky contact is obtained.

A Schottky gate FET including a gate electrode having a gate extension, a drain electrode and a drain contact layer overlying a semi-insulating substrate, wherein the gate extension overlies at least part of the drain electrode and the drain contact layer. The vertical overlapping between the gate extension and the drain contact region prevents the current reduction to make the circuit module mounting the Schottky gate FET non-usable.

A HEMT has an InAlAs layer (202), an InGaAs layer (203), a multiple δ-doped InAlAs layer (204) composed of n-type doped layers (204a) and undoped layers (204b) which are alternately stacked, an InP layer (205), a Schottky gate electrode (210), a source electrode (209a), and a drain electrode (209b) on an InP substrate (201). When a current flows in a region (channel region) of the InGaAs layer (203) adjacent the interface between the InGaAs layer (203) and the multiple δ-doped InAlAs layer (204), a breakdown voltage in the OFF state can be increased, while resistance to the movement of carriers passing through the multiple δ-doped InAlAs layer (204) as a carrier supplying layer is reduced.

SiC MESFETs are disclosed which utilize a semi-insulating SiC substrate which substantially free of deep-level dopants. Utilization of the semi-insulating substrate may reduce back-gating effects in the MESFETs. Also provided are SiC MESFETs with a two recess gate structure. MESFETS with a selectively doped p-type buffer layer are also provided. Utilization of such a buffer layer may reduce output conductance by a factor of 3 and produce a 3 db increase in power gain over SiC MESFETs with conventional p-type buffer layers. A ground contact may also be provided to the p-type buffer layer and the p-type buffer layer may be made of two p-type layers with the layer formed on the substrate having a higher dopant concentration. SiC MESFETs according to embodiments of the present invention may also utilize chromium as a Schottky gate material. Furthermore, an oxide-nitride-oxide (ONO) passivation layer may be utilized to reduce surface effects in SiC MESFETs. Also, source and drain ohmic contacts may be formed directly on the n-type channel layer, thus, the n⁺ regions need not be fabricated and the steps associated with such fabrication may be eliminated from the fabrication process. Methods of fabricating such SiC MESFETs and gate structures for SiC FETs as well as passivation layers are also disclosed.

In the rectifier, a barrier layer and a channel layer constitute a heterojunction portion, and a two-dimensional electron gas channel is generated in the vicinity of a boundary between the channel layer and the barrier layer. A Schottky gate electrode is connected to an anode ohmic electrode and extends from above the anode ohmic electrode over to the barrier layer and a recess formed in the barrier layer is covered with the Schottky gate electrode. The two-dimensional electron gas channel located just below the recess is depleted by the influence of the Schottky gate electrode in a state in which there is no application voltage. By virtue of the formation of the recess in the barrier layer, the threshold voltage at which electrons are generated in the two-dimensional electron gas channel located just below the gate electrode is lowered, and the rise voltage can be made lower than that of the conventional Schottky diode.

A method of forming a Schottky barrier contact to a semiconductor material, includes the following steps: depositing an iridium contact on a surface of the semiconductor material; and annealing the iridium contact to form a Schottky barrier contact to the semiconductor material. For an example of an iridium Schottky contact on an InAlAs semiconductor material, the annealing temperature is preferably in the range about 350° C. to 500° C.

A field effect transistor (FET) with novel field-plate structure relates to a Schottky gate FET structure with field plate thereon for high voltage operations. The structure and fabrication processes thereof not only provide a reliable way to produce high-voltage FETs, but also allow the integration of conventional low-voltage FETs on the same wafer.

A field effect transistor (FET) with novel field-plate structure relates to a Schottky gate FET structure with field plate thereon for increasing the operation voltage. The structure can eliminate surface damages of unpassivated region and degradation of the interface property of gate contacts during plasma etching of dielectric film for gate recesses, and can be reliably used in wireless and satellite communications.

There is provided a protection circuit of a field effect transistor having a structure which can be fabricated without restricting a pattern layout and without increasing a process step. A protection circuit of a field effect transistor is a protection circuit of a Schottky gate HFET, and is a circuit in which a forward direction diode and a reverse direction diode are cascade-connected to form a diode unit and two such diode units are connected in series, and a gate line connected to a gate electrode of the HFET is grounded through the protection circuit. The diodes are diodes formed integrally with the Schottky gate HFET which is protected against surge breakdown, and are constituted as Schottky barrier diodes made of an n+-GaAs cap layer formed on a GaAs substrate and Schottky electrodes formed on the n+-GaAs cap layer.

The invention discloses a Schottky gate array type terahertz modulator and a regulation and control method thereof. A periodic gate type metal-semiconductor surface plasmon waveguide structure is adopted, the characteristics of Schottky contact formed by a metal-semiconductor interface and superposition of the Schottky contact and terahertz surface plasmon polariton position are utilized, a positive electrode and a negative electrode are led in and voltage is exerted, so that the terahertz modulation function of the Schottky gate array type terahertz modulator is achieved. The Schottky gate array type terahertz modulator combines a waveguide optical microstructure with a semiconductor electron device together, so that the Schottky gate array type terahertz modulator is well integrated with other electronic components and systems, and the optical functions of terahertz wave transmission and resonance oscillation are achieved. The Schottky gate array type terahertz modulator works from 2.2THz to 3.2THz, the working frequency can be tuned along with the working voltage, the maximum modulation depth is 16dB, and the highest modulation rate is 22MHz. The Schottky gate array type terahertz modulator is an on-chip electronically-controlled high-speed terahertz modulator which is in a small type and can be integrated, and the application requirements for terahertz broadband wireless communications are met.

A enhance HEMT and a preparation method thereof, the enhanced HEMT includes a GaN epitaxial wafer, source and drain electrodes located at both ends of the GaN epitaxial wafer and a gate electrode located between the source and drain electrodes, the gate electrode comprises a plurality of concave gate grooves, wherein a gate metal layer is directly deposited on the surface of the concave gate groove to form a Schottky gate electrode, or a gate dielectric layer and a gate metal layer are sequentially deposited to form a MIS gate electrode, and the bottom of the concave gate groove is located ina barrier layer of a GaN epitaxial wafer, the total length of the concave gate groove is equal to a preset gate length, and sufficient gate control capability is ensured; The depth of each concave gate groove decreases sequentially in the direction away from the source electrode, so that the electron depletion degree in the channel decreases sequentially, and sufficient electrons are ensured in the channel, so that the characteristics of large current can be maintained on the basis of realizing the enhanced type, the on resistance of the channel is reduced, and the power consumption of the device is reduced.

The invention discloses a preparation method of a schottky gate field effect transistor. According to the preparation method, a two-dimensional material is prepared on a substrate firstly, then the substrate and the two-dimensional material are coated with photoresist in a spin coating manner, and photoetching exposure and developing are performed to expose source and drain electrode windows; metal is coated, and the photoresist is washed off, and next, annealing in gas atmosphere is performed to form a source electrode and a drain electrode; next, the whole piece of a sample is coated with photoresist in a spin coating manner, and photoetching exposure and developing are performed to expose a gate electrode window; and next, metal is coated, and the photoresist is washed off to form the schottky gate field effect transistor. The schottky gate field effect transistor has the advantages of small dimensions, high switch ratio, high mobility, capability of well eliminating a short-channel effect and the like, so that the application field of a two-dimensional material device can be expanded.

A junction field effect transistor is described. The transistor is made from a wide bandgap semiconductor material. The device comprise source, channel, drift and drain semiconductor layers, as well as p-type implanted or Schottky gate regions. The source, channel, drift and drain layers can be epitaxially grown. The ohmic contacts to the source, gate, and drain regions can be formed on the same side of the wafer. The devices can have different threshold voltages depending on the vertical channel width and can be implemented for both depletion and enhanced modes of operation for the same channel doping. The devices can be used for digital, analog, and monolithic microwave integrated circuits. Methods for making the transistors and integrated circuits comprising the devices are also described.

The invention discloses a GaN-based enhanced device with a gallium nitride insertion layer and a preparation method thereof. Since a gallium nitride layer is inserted into a barrier layer, in the preparation of a groove gate structure, corrosion can be stopped at the gallium nitride insertion layer automatically, so that different depths of groove corrosion effects can be realized through different insertion positions of the gallium nitride layer in the barrier layer, and control and adjustment of Schottky gate and MOS structure gate threshold voltage can be finished based on the structure above; the left barrier layer in proper thickness under the gallium nitride insertion layer can protect the trenches during groove corrosion effectively to prevent degradation of device performance; and the GaN-based enhanced device and the preparation method thereof have higher operability and repeatability, and facilitate industrial production.

The invention relates to a gallium nitride device schottky contact system with a composite metal barrier layer. The structure of a gallium nitride device successively comprises a substrate 11, a GaN buffer layer 12 and an AlGaN barrier layer 13 from bottom to top; a source electrode 14 is arranged at one end of the upper part of the AlGaN barrier layer; a drain electrode 15 is arranged at the other end of the upper part of the AlGaN barrier layer 13; an AlGaN/GaN HEMT gate electrode 16 is arranged above the AlGaN barrier layer 13 positioned between the source electrode 14 and the drain electrode 15; the AlGaN/GaN HEMT gate electrode 16 is a gate electrode provided with a schottky contact structure; and the schottky contact structure comprises a composite metal layer provided with a Ni metal layer, a Mo metal layer, a Ti metal layer, a Pt metal layer and a Y metal layer. A multi-layered metal system of a schottky gate of the gallium nitride device and an epitaxial layer of the multi-layered metal system have excellent thermal matching property, and reliability of the gallium nitride device can be greatly improved.

The invention provides a longitudinal-channel SiC Schottky gate bipolar transistor. The longitudinal-channel SiC Schottky gate bipolar transistor comprises an N+ silicon carbide substrate, an emitter contact metal layer, a P+ buffer layer, a P- drift region, a P+ current collection region and a collector contact metal layer and also comprises at least two vertical grooves, wherein the emitter contact metal layer is formed on a surface of the N+ silicon carbide substrate, the P+ buffer layer is formed on the N+ silicon carbide substrate, the P- drift region is formed on the P+ buffer layer, the P+ current collection region is formed on the P- drift region, the collection contact metal layer is formed on the P+ current collection region, the at least two vertical grooves are formed in the P- drift region, and a Schottky gate metal layer is formed on each groove. In the device provided by the invention, an upper part structure of a traditional insulated gate bipolar transistor (IGBT) device is substituted by employing a channel structure of a longitudinal-channel junction field-effect transistor (JFET) device on the P- drift region and taking Schottky contact metal as a device gate, and the width of a channel region of the device is 0.5-1.5 micrometers; and the device has the advantages of simple fabrication process, low cost, high device current grain and the like and can be used for a switching voltage-stabilization power supply, electric energy conversion, automobile electron, petroleum drilling equipment and the like.

A transistor component and its manufacturing method, the component includes: a semiconductor substrate, a drain, a source, a gate metal seed layer formed on the semiconductor substrate, which has a gel-like substance layer And a plurality of metal seeds and a Schottky contact metal gate are formed on the gate metal seed layer. The method includes: step A: providing a semiconductor substrate; step B: forming a drain and a source on the semiconductor substrate; step C: defining a region of a gate metal seed layer on the semiconductor substrate; Step D: performing a sensitization and activation process to form the gate metal seed layer on the semiconductor substrate; and Step E: performing an electroless plating process to form a Schottky contact metal gate on the gate metal crystal above the seed layer.

A Schottky gate field effect transistor with high speed and simple structure is provided. The Schottky gate field effect transistor includes: a source, a channel and a drain formed by one organic conductive material, in which the source, channel and drain are formed in a continuous structure within an organic conductor; a gate electrode functioning as a metal gate on one surface of the organic conductor; a Schottky barrier formed by contact between the gate electrode and the organic conductor, in which the region overlapping with the Schottky contact is the channel region.

The invention discloses a gallium nitride normally-off device with a mixed gate electrode structure and a preparation method of the gallium nitride normally-off device. The gallium nitride normally-off device comprises a buffer layer, a GaN channel layer, an AlGaN layer and a P-GaN cap layer which are sequentially arranged on a substrate layer, two ohmic electrodes which are arranged on the AlGaN layer, gate dielectric layers which are arranged on the P-GaN cap layer and on the two sides of the P-GaN cap layer, a passivation layer which is arranged on the AlGaN layer between the ohmic electrode and the gate dielectric layer on the two sides of the P-GaN cap layer, and a gate electrode which is arranged on the gate dielectric layer and filled in the groove of the gate dielectric layer. The gate electrode on the gate dielectric layer on the P-GaN cap layer and the gate electrodes filled in the plurality of grooves form a mixed gate structure of an MIS gate electrode structure and a Schottky gate electrode structure; and the gate electrodes on the gate dielectric layers on the two sides of the P-GaN cap layer and the gate dielectric layers on the two sides of the P-GaN cap layer form a field plate structure. The threshold voltage of the gate electrode of the device is improved, the switching frequency of the device is improved, and meanwhile the long-term reliability of the gate electrode of the device is improved.

The invention discloses InAs/AlSb HEMT and MOS-HEMT device manufacturing methods, mainly to reduce on-state resistance of a device and solve the problem of gate current leakage. The InAs/AlSb HEMT device manufacturing method comprises the following process steps of: 1) epitaxial material growth, 2) mesa isolation, 3) ohmic contact manufacturing, 4) schottky gate contact manufacturing, 5) Pad deposition and 6) passivation. The InAs/AlSb MOS-HEMT device manufacturing method comprises the following process steps of: 1) epitaxial material growth, 2) mesa isolation, 3) ohmic contact manufacturing, 4) insulated gate manufacturing, 5) Pad deposition and 6) passivation. A gate slot etching step is saved, the gate current leakage is reduced, and the on-state resistance of the device is also reduced.