Showing papers on "Gallium nitride published in 1988"

Critical evaluation of the status of the areas for future research regarding the wide band gap semiconductors diamond, gallium nitride and silicon carbide

Abstract: The extreme thermal and electronic properties of diamond and of silicon carbide, and the direct band gap of gallium nitride, provide multiplicative combinations of attributes which lead to the highest figures of merit for any semiconductor materials for possible use in high power, high speed, high temperature and high frequency applications. The deposition of monocrystalline diamond, at or below 1 atm total pressure and at a temperature T , has been achieved on diamond substrates; the deposited film has been polycrystalline on all other substrates but the achievement is no less significant. For electronic applications, heteroepitaxy of single-crystal films of diamond, an understanding of mechanisms of nucleation and growth, methods of impurity introduction and activation, and further device development must be achieved. Stoichiometric gallium nitride free of nitrogen vacancies has apparently not been obtained. Thus, knowledge of the defect chemistry of this material, the growth of semiconducting films on foreign substrates, and the development of insulating layers and of their low temperature deposition as well as device fabrication procedures must be achieved. By contrast, all of these problems have already been solved for silicon carbide, including the operation of a MOSFET at 923 K — the highest operating temperature ever reported for a field-effect device. However, considerable research remains to be done regarding the development of large silicon carbide substrates, of ohmic and rectifying contacts, of new types of devices, and of low temperature techniques for the deposition of insulating layers. Fugitive donor and acceptor species in unintentionally doped samples must also be identified and controlled.

Substrate-polarity dependence of metal-organic vapor-phase epitaxy-grown GaN on SiC

Abstract: Single‐crystal gallium nitride was grown on each of the two polar {0001} planes of 6H‐silicon carbide substrates utilizing metal‐organic vapor‐phase epitaxy. The substrate polarity is clearly shown to strongly influence the surface morphology and the photoluminescence property of the layer. The examination of the layer surfaces using x‐ray photoelectron spectroscopy revealed that {0001} GaN grown on the basal planes of SiC changes its polarity in accordance with the substrate polarity.

Single crystal semiconductor substrate articles and semiconductor devices comprising same

Abstract: A textured substrate is disclosed which is amenable to deposition thereon of epitaxial single crystal films of materials such as diamond, cubic boron nitride, boron phosphide, beta-silicon carbide, and gallium nitride. The textured substrate comprises a base having a generally planar main top surface from which upwardly extends a regular array of posts, the base being formed of single crystal material which is crystallographically compatible with epitaxial single crystal materials to be deposited thereon. The single crystal epitaxial layers are formed on top surfaces of the posts which preferably have a quadrilateral cross-section, e.g., a square cross-section whose sides are from about 0.5 to about 20 micrometers in length, to accommodate the formation of substantially defect-free, single crystal epitaxial layers thereon. The single crystal epitaxial layer may be selectively doped to provide for p-type and p + doped regions thereof, to accommodate fabrication of semiconductor devices such as field effect transistors.

Gallium nitride group semiconductor light emitting diode and the process of producing the same

Abstract: A thin film of SiO₂ (32) is patterned on an N layer consist­ing of N-type Al x Ga 1-x N (inclusive of x = 0) (31). Next, I-type Al x Ga 1-x N (inclusive of x = 0) (33) is selectively grown and the portion on the N layer (31) grows into an I-layer (33) consisting an active layer of a light emitting diode, and that on the SiO₂ thin film (32) grows into a conductive layer (34). Electrodes (35,36) are formed on the I-layer (33) and conductive layer (34) to constitute the light emitting diode. Also, on the surface a ({11 2 0}) of a sapphire substrate (24), a buffer layer (30) consisting of aluminum nitride is formed, onto which a gallium nitride group semiconductor (31) is formed.

Evolution of the GaAs(001) Surface Physico-Chemical Characteristics and Electrical Properties of the Si3N4/GaAs Interface with the NH3Photolysis Treatment of the GaAs Surface.

Abstract: Cleaning treatments of GaAs(001) by UV decomposition of NH3 has been studied by means of X-ray photoemission spectroscopy (XPS) and X-ray photoelectron diffraction (XPD). This photolysis treatment is shown to decompose the surperficial oxides and to remove the carbon of contamination. The surface cleaning is followed by the formation of gallium nitride overlayers. When used prior to UVCVD silicon nitride deposition, this treatment is shown to improve the electrical characteristics of the Si3N4/GaAs MIS structure.

Growing of gallium nitride crystal

Abstract: PURPOSE:To make it possible to grow a gallium nitride crystal in a low ratio of V/III at low temperature, by using hydrazine as a nitrogen raw material and triethyl gallium as a gallium raw material CONSTITUTION:N2H2 is used instead of conventional NH2 as a N2 raw material and triethyl gallium (TEG) having a low decomposition temperature is used instead of trimethyl gallium (TMG) as a Ga raw material For example, a pre-treated substrate 7 is put on a carbon susceptor 1 so as to grow GaN on the (111)B face of the GaAs substrate 7 using a vertical type reduced pressure MOCVD apparatus TEG 2 and N2H4 are both kept at about 20 degC to keep saturated steam pressure constant, bubbled with H2 and fed using H2 as a carrier gas into a reaction tube 4 TEG and N2H4 are fed in each about 02 and 20cc/min flow rate, about 8l/min total flow rates, about 100Torr pressure and about 15cm/sec average flow velocities

Gallium nitride group compound semiconductor and luminous element comprising it and the process of producing the same

Abstract: A thin film of SiO₂ is patterned on an N layer consisting of N-type AlxGa1-xN (inclusive of x = 0). Next, I-type AlxGa1-xN (inclusive of x = 0) is selectively grown and the portion on the N layer grows into an I-layer consisting an active layer of a light emitting diode, and that on the SiO₂ thin film grows into a conductive layer. Electrodes are formed on the I-layer and conductive layer to constitute the light emitting diode. Also, on the surface a ({1120}) of a sapphire substrate, a buffer layer consisting of aluminum nitride is formed, onto which a gallium nitride group semiconductor is formed.

Growth Of Gallium Nitride On Silicon Carbide By Molecular Beam Epitaxy

Abstract: Gallium nitride (GaN) is a compound semicon-ductor with a direct, wide bandgap (3.5 eV at 300K) and a large saturated electron drift veloc-ity. This unique combination of properties pro-vides the potential for fabrication of short wave-length (near UV and blue) semiconductor lasers, LEDs and detectors as well as transit-time-limited (IMPATT, etc.) microwave power amplifiers from this material. However, all GaN previously pro-duced has possessed a high n-type carrier concen-tration which has limited its potential. This phenomenon has been almost invariably associated with the presence of nonequilibrium nitrogen va-cancies. This paper reports growth of GaN by mod-ified MBE techniques in order to reduce the nitro-gen vacancies. The primary advantages of these MBE-based techniques are low growth temperature and high nitrogen activity. A standard effusion cell was used for the gallium source, but for ni-trogen, a microwave glow discharge was used to ac-tivate the nitrogen prior to deposition. The films were deposited on (100) 3-SiC and (0001) Al203 substrates. Growth results and preliminary film characterization will be presented.

Manufacture of gallium nitride film

Abstract: PURPOSE:To obtain a uniform gallium nitride film by reducing the pressure of an atmosphere exposing a substrate in a gas containing a compound which contains a gallium atom, then by reducing the pressure of the atmosphere exposing in ammonia or hydrazine gas and by irradiating ultraviolet rays each time. CONSTITUTION:A substrate is subjected to the repetition of the first process wherein the substrate is exposed in a gas containing a compound which contains a gallium atom, the second process of reducing the pressure of the atmosphere near the surface of the substrate, the third process of irradiating ultraviolet rays on the surface of the substrate reducing the pressure of the atmosphere, the fourth process of exposing the substrate in a gas containing ammonia or hydrazine, the fifth process of reducing the pressure of the atmosphere near the surface of the substrate and the sixth process of irradiating the ultraviolet rays on the surface of the substrate reducing the pressure of the atmosphere. A gas-state compound which contains the Ga atom and a non-oxidizing gas such as H2 or He are used for the gas containing a compound which contains the Ga atom. A mixture of NH3 or N2H4 and a non-oxidizing gas is used for a gas which contains NH3 or N2H4. This enables to obtain a gallium nitride film which has good film quality and uniform film thickness.

Production of gallium nitride thin film

Abstract: PURPOSE:To enable the formation of a gallium nitride thin film having high crystallinity and low impurity content at a low temperature, by reacting excited gallium with excited nitrogen and dissociated hydrogen CONSTITUTION:A gallium nitride thin film can be formed on a substrate by reacting excited gallium or gallium-containing compound with excited nitrogen or nitrogen-containing compound and dissociated hydrogen Gallium nitride can be synthesized at a low temperature because a reaction of an excited component is substantially a reaction having no activation energy The high internal energy of the dissociated hydrogen promotes the reaction and migration of atoms on a substrate and the removal of surface impurities Furthermore, a thin film having excellent crystallinity and electrical properties can be formed at a low temperature by the passivation effect of dangling bond with the hydrogen atom

Film growing method of hydrogenated gallium/trialkylamine adduct and iii-v compound

Abstract: Adduct of the formula H3GaNR3 wherein each R is independently selected from lower alkyl groups having at least 2 carbon atoms, and a process for depositing gallium nitride, gallium arsenide, or gallium phosphide films, using the above adduct as a source of nitride (for the nitride film) and gallium. Arsenic and phosphorus compounds can also be added for deposition gallium compounds of those elements. The process can also be performed using the analogous trimethylamine adduct.

The Growth of Gallium Nitride Films Via the Innovative Technique of Atomic Layer Epitaxy

Abstract: : Gallium nitride (GaN) is a wide bandgap (3.45 eV at 300K) III-V compound semiconductor. The large direct bandgap and high electron drift velocity of GaN are important properties in the performance of short wavelength optical devices and high power microwave devices. Immediate applications that would be greatly enhanced by the availability of GaN and/or AlxGa1-xN devices include threat warning systems (based on the ultraviolet (UV) emission from the exhaust plumes of missiles) and radar systems (which require high power microwave generation). Important future applications for devices produced from these materials include blue and ultraviolet semiconductor lasers, blue light emitting diodes (LEDs) and high temperature electronic devices. This report discusses this material.

On the mechanism of polarized electroluminescence from light-emitting structures based on GaN

Abstract: Investigations of photoelectromotive force and photoconductivity are made in order to find the mechanism of electroluminescence in the GaN: (Zn, O) light-emitting structures. They enable to detect the existence of two channels of current flow in the structures investigated. One of them is a diode circuit with a potential barrier of ≈ 3 eV. This channel of conductivity is responsible for the unipolar electroluminescence with Emax ≈ 2.6 eV and with polarization degree up to ≈ 60%. The large value of the potential barrier height shows that gallium nitride may be of p-type conductivity. The analysis of the peculiarities of the growth and doping of GaN does not contradict this supposition. [Russian Text Ignored].