Hiratsuka, Japan
Hiratsuka, Japan

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Iso K.,Japan Pionics Co. | Takaki R.,Japan Pionics Co. | Ishihama Y.,Japan Pionics Co. | Inagawa T.,Mitsubishi Group | Takahashi Y.,Japan Pionics Co.
Physica Status Solidi (A) Applications and Materials Science | Year: 2010

InGaN/GaN-based light emitting diodes (LEDs) can be grown by using metal organic chemical vapor deposition (MOCVD) to make eight, 3-inch diameter wafers with a thin, tapered reactor cell at atmospheric pressure. The reactor configuration was optimized for the purpose of improving the GaN growth rate and its in-plane distribution. The growth rate and the layer uniformity of GaN were improved when the reactor cell was narrowed down and tapered. The on-wafer deviation of the electroluminescence (EL) peak wavelength and power were 5 nm and within 4%, respectively, except at the edge. The full width at half maximum (FWHM) of EL spectrum for an LED grown at atmospheric pressure was consistently smaller than that of one grown at reduced pressure over the entire wavelength range. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Iuchi T.,Toyo University | Toyoda Y.,Toyo University | Seo T.,Japan Pionics Co.
Review of Scientific Instruments | Year: 2013

We studied the spectral and directional emissivities of silicon wafers using an optical polarization technique. Based on simulation and experimental results, we developed two radiation thermometry methods for silicon wafers: one is based on the polarized emissivity-invariant condition and the other is based on the relationship between the ratio of the p- and s-polarized radiance and the polarized emissivity. These methods can be performed at temperatures above 600 °C and over a wide wavelength range (0.9-4.8 μm), irrespective of the dielectric film thickness and the substrate resistivity, which depends on the dopant concentration. The temperature measurements were estimated to have expanded uncertainties (k = 2) of less than 5 °C. With a view to practically applying these methods, we investigated a method to reduce the intense background radiance produced by high-intensity heating lamps. We found that the background radiance can be greatly reduced by using a radiometer that is sensitive to wavelengths of 4.5 or 4.8 μm and suitable geometrical arrangements of a quartz plate. This opens up the possibility of using the two proposed radiation thermometry methods in practical applications. © 2013 American Institute of Physics.


Patent
Japan Pionics Co. | Date: 2015-12-17

The present invention provides a method of processing discharge gas containing ammonia, hydrogen, nitrogen, and an organic metal compound discharged from the production process of a gallium nitride compound semiconductor. The discharge gas is brought into contact with a cleaning agent prepared by impregnating an alkali metal compound with a metal oxide to remove the organic metal compound from the discharge gas. The discharge gas from which an organic metal compound is removed is brought into contact with an ammonia decomposition catalyst on heating to decompose the ammonia into nitrogen and hydrogen. The discharge gas in which ammonia is decomposed is brought into contact with palladium alloy membrane on heating to recover hydrogen that has penetrated through the palladium alloy membrane. After an organic metal compound is removed to liquefy the ammonia contained in the discharge gas as described above, a pressurization process and a cooling process is conducted by a heat pump to pressurize and cool the discharge gas from which an organic metal compound is removed to liquefy the ammonia contained in the discharge gas and separate the liquefied ammonia from hydrogen and nitrogen so as to recover the liquefied ammonia. The recovered hydrogen and ammonia are supplied to and reused in the production process of a gallium nitride compound semiconductor.


The present invention provides a method of processing discharge gas containing ammonia, hydrogen, nitrogen, and an organic metal compound discharged from the production process of a gallium nitride compound semiconductor. The discharge gas is brought into contact with a cleaning agent prepared by impregnating an alkali metal compound with a metal oxide to remove the organic metal compound from the discharge gas. The discharge gas from which an organic metal compound is removed is brought into contact with an ammonia decomposition catalyst on heating to decompose the ammonia into nitrogen and hydrogen. The discharge gas in which ammonia is decomposed is brought into contact with palladium alloy membrane on heating to recover hydrogen that has penetrated through the palladium alloy membrane. After an organic metal compound is removed to liquefy the ammonia contained in the discharge gas as described above, a pressurization process and a cooling process is conducted by a heat pump to pressurize and cool the discharge gas from which an organic metal compound is removed to liquefy the ammonia contained in the discharge gas and separate the liquefied ammonia from hydrogen and nitrogen so as to recover the liquefied ammonia. The recovered hydrogen and ammonia are supplied to and reused in the production process of a gallium nitride compound semiconductor.


There are provided methods capable of easily and efficiently recovering and recycling ammonia from exhaust gas containing a small amount of ammonia, the exhaust gas being exhausted from a production process of a gallium nitride compound semiconductor. The method of recovering ammonia includes filtering exhaust gas containing ammonia, hydrogen, nitrogen, and a solid compound with a filter to remove the solid compound from the exhaust gas; pressurizing and cooling the filtered exhaust gas with a heat pump to liquefy ammonia contained in the filtered exhaust gas; and separating liquefied ammonia from hydrogen and nitrogen to recover liquefied ammonia. The method of recycling ammonia includes evaporating recovered liquid ammonia; mixing the evaporated ammonia with another crude ammonia to obtain mixed gas; purifying the mixed gas; and supplying the purified gas to the production process of a gallium nitride compound semiconductor.


The present invention is to provide a means for easily replacing palladium alloy capillaries in a hydrogen purification device formed by using hydrogen separation membrane formed from the palladium alloy capillaries. The hydrogen purification device can be easily disassembled into a palladium alloy membrane unit and a storage structure thereof. A palladium alloy membrane unit is provided with a plurality of palladium alloy capillaries, a disk-shaped tube sheet supporting the palladium alloy capillaries, a pure hydrogen discharge pipe having a cylinder being in close contact with a periphery of the tube sheet at one end, a joint connecting with a pure hydrogen outlet of the storage structure at the other end, and preferably a joint being in close contact with an opening of a container of the storage structure at a position between the cylinder and the outlet joint. The storage structure is provided with a container storing the palladium alloy membrane unit, a heater, a raw material hydrogen inlet, an impurity-containing gas outlet, and a pure hydrogen outlet, a member provided on the pure hydrogen outlet, the member connecting with a joint provided at one end of the palladium alloy membrane unit, and preferably a member provided on the opening of the container, the member being in close contact with a joint provided on the cylinder of the palladium alloy membrane unit.


A cleaning apparatus a metal organic chemical vapor deposition (MOCVD) device incorporating a susceptor rotatably holding the plurality of substrate holders through a rotating mechanism of a bearing; and a cleaning method for efficiently removing deposits from components of the device. The cleaning apparatus includes storage for the susceptor and the plurality of substrate holders; a means for rotating the susceptor and/or a means for rotating the plurality of substrate holders; a heater; a cleaning gas-introducing port; and a cleaning gas-discharging port. The susceptor holding the plurality of substrate holders is stored in the cleaning apparatus after the device is used for vapor phase epitaxy, and cleaning gas is introduced to the susceptor while the susceptor and/or each of the substrate holders is rotated, so as to remove deposits deposited during vapor phase epitaxy.


Patent
Japan Pionics Co. | Date: 2015-06-10

The present invention provides ammonia purification means to remove impurities such as oil with a negative effect on vapor deposition from inexpensive commercially available industrial crude ammonia and from crude ammonia recovered from the gallium nitride compound semiconductor process and to continuously supply the purified ammonia to the gallium nitride compound semiconductor process. The oil removing device removing oil from crude ammonia containing oil as impurities includes an oil filter cylinder accommodating a filtration element cylindrically formed from a filtration membrane processed into a shape of pleat, honeycomb, or space structure; and an oil adsorption cylinder filled with activated carbon. The ammonia purification apparatus is provided with the oil removing device; a catalyst cylinder filled with a catalyst containing nickel as an active component; and an adsorption cylinder filled with synthetic zeolite.


Patent
Japan Pionics Co. | Date: 2015-10-02

The present invention is to provide a method for refining hydrogen with a hydrogen refining device in which the inside of a cell is divided into a primary side space and a secondary side space by palladium alloy capillaries each having one end being closed and a tube sheet supporting the open end of the palladium alloy capillaries, in which impurity-containing hydrogen is introduced from the primary side space to allow hydrogen to permeate the palladium alloy capillaries so as to collect pure hydrogen from the secondary side space. The method for refining hydrogen has a capability of decreasing the removed amount of gas containing impurities and efficiently collecting pure hydrogen from the secondary side space. From hydrogen with 1000 ppm or less of impurities as raw material hydrogen, gas containing impurities that does not penetrate the palladium alloy capillaries is removed from the primary side space at the flow rate of 10% or less of the introduction flow rate of the raw material hydrogen. Furthermore, gas containing impurities that does not penetrate the palladium alloy capillaries is removed from the primary side space at a flow rate based on the content of impurities contained in raw material hydrogen.


The present invention is to provide a means for easily replacing palladium alloy capillaries in a hydrogen purification device formed by using hydrogen separation membrane formed from the palladium alloy capillaries. The hydrogen purification device can be easily disassembled into a palladium alloy membrane unit and a storage structure thereof. A palladium alloy membrane unit is provided with a plurality of palladium alloy capillaries, a disk-shaped tube sheet supporting the palladium alloy capillaries, a pure hydrogen discharge pipe having a cylinder being in close contact with a periphery of the tube sheet at one end, a joint connecting with a pure hydrogen outlet of the storage structure at the other end, and preferably a joint being in close contact with an opening of a container of the storage structure at a position between the cylinder and the outlet joint. The storage structure is provided with a container storing the palladium alloy membrane unit, a heater, a raw material hydrogen inlet, an impurity-containing gas outlet, and a pure hydrogen outlet, a member provided on the pure hydrogen outlet, the member connecting with a joint provided at one end of the palladium alloy membrane unit, and preferably a member provided on the opening of the container, the member being in close contact with a joint provided on the cylinder of the palladium alloy membrane unit.

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