252results about How to "Wide bandgap" patented technology

To reduce power consumption of a semiconductor integrated circuit and to reduce delay of the operation in the semiconductor integrated circuit, a plurality of sequential circuits included in a storage circuit each include a transistor whose channel formation region is formed with an oxide semiconductor, and a capacitor whose one electrode is electrically connected to a node that is brought into a floating state when the transistor is turned off. By using an oxide semiconductor for the channel formation region of the transistor, the transistor with an extremely low off-state current (leakage current) can be realized. Thus, by turning off the transistor in a period during which power supply voltage is not supplied to the storage circuit, the potential in that period of the node to which one electrode of the capacitor is electrically connected can be kept constant or almost constant. Consequently, the above objects can be achieved.

A method of fabricating AlGaN / GaN enhancement-mode heterostructure field-effect transistors (HFET) using fluorine-based plasma immersion or ion implantation. The method includes: 1) generating gate patterns; 2) exposing the AlGaN / GaN heterostructure in the gate region to fluorine-based plasma treatment with photoresist as the treatment mask in a self-aligned manner; 3) depositing the gate metal to the plasma treated AlGaN / GaN heterostructure surface; 4) lifting off the metal except the gate electrode; and 5) high temperature post-gate annealing of the sample. This method can be used to shift the threshold voltage of a HFET toward a more positive value, and ultimately convert a depletion-mode HFET to an enhancement-mode HFET (E-HFET).

AlGaN / GaN HEMTs are disclosed having a thin AlGaN layer to reduce trapping and also having additional layers to reduce gate leakage and increase the maximum drive current. One HEMT according to the present invention comprises a high resistivity semiconductor layer with a barrier semiconductor layer on it. The barrier layer has a wider bandgap than the high resistivity layer and a 2DEG forms between the layers. Source and drain contacts contact the barrier layer, with part of the surface of the barrier layer uncovered by the contacts. An insulating layer is included on the uncovered surface of the barrier layer and a gate contact is included on the insulating layer. The insulating layer forms a barrier to gate leakage current and also helps to increase the HEMT's maximum current drive. The invention also includes methods for fabricating HEMTs according to the present invention. In one method, the HEMT and its insulating layer are fabricated using metal-organic chemical vapor deposition (MOCVD). In another method the insulating layer is sputtered onto the top surface of the HEMT in a sputtering chamber.

An object of the present invention is to provide a novel aromatic amine compound, and a light-emitting element, a light-emitting device, and an electronic appliance with high luminous efficiency. An aromatic amine compound expressed by General Formula (1) and a light-emitting element, a light-emitting device, and an electronic appliance formed using the aromatic amine compound expressed by General Formula (1) are provided. By the use of the aromatic amine compound expressed by General Formula (1), the light-emitting element, the light-emitting device, and the electronic appliance can have high luminous efficiency.

The invention relates to a method for preparing a graphite-phase carbon nitride (g-C3N4) material. The method includes the steps that a carbon nitride precursor and ammonium salt are evenly mixed, and then calcination is conducted so that the porous g-C3N4 material can be obtained. The ammonium salt is any one of ammonium base salts capable of generating ammonia gas through thermal decomposition or is the combination of at least two of the ammonium base salts. In the preparation process of the g-C3N4 material, the ammonium salt is added into the carbon nitride precursor to be mixed. In the high-temperature calcining process, the ammonium salt is subjected to pyrogenic decomposition to generate gas, a pore-forming effect on the g-C3N4 material is achieved, and the cellular porous g-C3N4 material is obtained. In the preparation process of the g-C3N4 material, template agents are not used, and thus the method is simple, efficient and environmentally friendly; the prepared g-C3N4 material is high in photocatalytic activity and can be used in the pollution control processes such as exhaust gas and wastewater treatment.

A method of fabricating AlGaN / GaN enhancement-mode heterostructure field-effect transistors (HFET) using fluorine-based plasma immersion or ion implantation. The method includes: 1) generating gate patterns; 2) exposing the AlGaN / GaN heterostructure in the gate region to fluorine-based plasma treatment with photoresist as the treatment mask in a self-aligned manner; 3) depositing the gate metal to the plasma treated AlGaN / GaN heterostructure surface; 4) lifting off the metal except the gate electrode; and 5) high temperature post-gate annealing of the sample. This method can be used to shift the threshold voltage of a HFET toward a more positive value, and ultimately convert a depletion-mode HFET to an enhancement-mode HFET (E-HFET).

The invention discloses a thermally activated delayed fluorescence material, which has a structure shown as formula I in the specification. In the formula I, a maximum of two of R1-R5 are H, and the balance are electron-donating groups. The molecular formula of the thermally activated delayed fluorescence material contains one cyano group and at most two H, and the balance are electron-donating groups. The structure has the advantages that: 1) single cyano group has weak electron-withdrawing ability, wider band gap (2.5ev-3.5ev) materials can be obtained, thus being conducive to construction of blue-light emitting materials; 2) single cyano material has shallower LUMO energy level (about 2.7eV), and has weaker dependence on the main material; and 3) the raw material synthesis is easier, and the price is cheaper.

A semiconductor apparatus includes a semiconductor chip 61 including a power semiconductor device using a wide band gap semiconductor, base materials 62 and 63, first and second intermediate members 65 and 68a, a heat conducting member 66, a radiation fin 67, and an encapsulating material 68 for encapsulating the semiconductor chip 61, the first and second intermediate member 65 and 68a and the heat conducting member 66. The tips of the base materials 62 and 63 work respectively as external connection terminals 62a and 63a. The second intermediate member 68a is made of a material with lower heat conductivity than the first intermediate member 65, and a contact area with the semiconductor chip 61 is larger in the second intermediate member 68a than in the first intermediate member.

To increase the frequency of input of image signals in terms of design in a field-sequential liquid crystal display device. Image signals are concurrently supplied to pixels provided in a plurality of rows among pixels arranged in matrix in a pixel portion of the liquid crystal display device. Thus, the frequency of input of an image signal to each pixel can be increased without change in response speed of a transistor or the like included in the liquid crystal display device.

A method for and devices utilizing monolithic integration of enhancement-mode and depletion-mode AlGaN / GaN heterojunction field-effect transistors (HFETs) is disclosed. Source and drain ohmic contacts of HFETs are first defined. Gate electrodes of the depletion-mode HFETs are then defined. Gate electrodes of the enhancement-mode HFETs are then defined using fluoride-based plasma treatment and high temperature post-gate annealing of the sample. Device isolation is achieved by either mesa etching or fluoride-based plasma treatment. This method provides a complete planar process for GaN-based integrated circuits favored in high-density and high-speed applications.

An object of the present invention is to provide a novel aromatic amine compound, and a light-emitting element, a light-emitting device, and an electronic appliance with high luminous efficiency. An aromatic amine compound expressed by General Formula (1) and a light-emitting element, a light-emitting device, and an electronic appliance formed using the aromatic amine compound expressed by General Formula (1) are provided. By the use of the aromatic amine compound expressed by General Formula (1), the light-emitting element, the light-emitting device, and the electronic appliance can have high luminous efficiency.

At present, a forming process of a base film through an amorphous silicon film is conducted in respective film forming chambers in order to obtain satisfactory films. When continuous formation of the base film through the amorphous silicon film is performed in a single film forming chamber with the above film formation condition, crystallization is not sufficiently attained in a crystallization process. By forming the amorphous silicon film using silane gas diluted with hydrogen, crystallization is sufficiently attained in the crystallization process even with the continuous formation of the base film through the amorphous silicon film in the single film forming chamber.

To provide a highly integrated semiconductor memory device. To provide a semiconductor memory device which can hold stored data even when power is not supplied. To provide a semiconductor memory device which has a large number of write cycles. The degree of integration of a memory cell array is increased by forming a memory cell including two transistors and one capacitor which are arranged three-dimensionally. The electric charge accumulated in the capacitor is prevented from being leaking by forming a transistor for controlling the amount of electric charge of the capacitor in the memory cell using a wide-gap semiconductor having a wider band gap than silicon. Accordingly, a semiconductor memory device which can hold stored data even when power is not supplied can be provided.

A structure for the n-type contact layer in the GaN-based MQW LEDs is provided. Instead of using Si-doped GaN as commonly found in conventional GaN-based MQW LEDs, the n-type contact layer provided by the present invention achieves high doping density (>1×1019 cm−3) and low resistivity through a superlattice structure combining two types of materials, AlmInnGa1-m-nN and AlpInqGa1-p-qN (0≦m, n<1, 0<p, q<1, p+q≦1, m<p), each having its specific composition and doping density. In addition, by controlling the composition of Al, In, and Ga in the two materials, the n-type contact layer would have a compatible lattice constant with the substrate and the epitaxial structure of the GaN-based MQW LEDs. This n-type contact layer, therefore, would not chap from the heavy Si doping, have a superior quality, and reduce the difficulties of forming n-type ohmic contact electrode. In turn, the GaN-based MQW LEDs would require a lower operation voltage.

In a preferred embodiment, a light emitting device comprising: a polar template; a p-type layer grown on the polar template; the p-type layer having a first polarization vector; the first polarization vector having a first projection relative to a growth direction; an n-type layer grown on the p-type layer; the n-type layer having a second polarization vector; the second polarization vector having a second projection relative to said growth direction that is larger than the first projection of the first polarization vector for the p-type layer; the n-type layer and p-type layer forming an interface; whereby the first polarization vector in the p-layer and second polarization vector in the n-layer create a discontinuity at the interface resulting in a negative charge appearing at the interface. In another preferred embodiment, a light emitting device comprising: a polar template; a n-type layer grown on the template; the n-type layer having a first polarization vector; the first polarization vector having a first projection relative to a growth direction; an p-type layer grown on the n-type layer; the p-type layer having a second polarization vector; the second polarization vector having a second projection relative to said growth direction that is larger than the first projection of the first polarization vector for the p-type layer; the n-type layer and p-type layer forming an interface; whereby the first polarization vector in the p-layer and second polarization vector in the n-layer create a discontinuity at the interface resulting in a negative charge appearing at the interface.