Mitsubishi Denki Kabushiki Kaisha

Kaoru Kadoiwa

Manabu Kato

Takashi Motoda

Tatsuya Kimura

Yoshitsugu Yamamoto

Zempei Kawazu

Takuji Sonoda

Nariaki Fujii

An epitaxial growth apparatus includes a substrate heating member, a growth chamber, a molecular beam source, a nozzle for ejecting a gaseous source material, an exhaust pipe, and a vacuum chamber. When a gate valve is opened between the vacuum chamber and the growth chamber, gas is exhausted from the growth chamber, and the pressure in the growth chamber is rapidly reduced. The transition from a state where the degree of vacuum is low to a state where the degree of vacuum is high is performed rapidly. Therefore, one crystalline growth apparatus is sufficient for freely selecting among growth modes to achieve desired thickness and controllability of the carrier concentration in an epitaxially grown layer. One mode requires selectivity and another mode suppresses dopant concentration for epitaxial growth of layers of an optical device or of a microwave device.

Epitaxial crystal growth apparatus

An MBE apparatus includes a reaction chamber in which a molecular beam of a gas irradiates a substrate for crystal growth; a gas bomb containing the gas; a regulator for reducing the pressure of the gas from the gas bomb; a pressure control apparatus having one or more anode and cathode electrodes, a coil for generating a magnetic field applied to the supplied gas, and a controller for controlling the electric field between the anode and cathode electrodes, the area of the anode and cathode electrodes, and the magnetic field generated by the coil, so that a molecular beam irradiates the substrate with the gas supplied. The supply of the gas may be quickly varied with high reproducibility and high precision. In addition, a semiconductor layer having a uniform carrier concentration can be easily formed on the semiconductor substrate or a semiconductor layer having a uniform composition ratio can be easily formed on the semiconductor substrate.

MBE apparatus and gas branch piping apparatus

A material supplying apparatus includes a container for storing a solution; an inlet pipe for introducing a carrier gas and an outlet pipe; electrodes disposed in the container over the depth direction of the container and forming a capacitor; and apparatus for calculating a residual amount of the solution in the container from the capacitance of the capacitor formed by the electrodes. The solution is used as the dielectric of the capacitor formed in the container and the capacitance varies according to the quantity of solution so that the residual amount of the solution and the time to replenish the solution are calculated in a simple structure having no moving parts.

Material supplying apparatus

A multiquantum barrier (MQB) structure includes a first superlattice layer and a second superlattice layer disposed continuously with the first superlattice layer. The first superlattice layer includes well layers having the same thickness and barrier layers having the same thickness, the well layers and barrier layers being alternatingly laminated. The second superlattice layer includes well layers having the same thickness, the well and barrier layers being alternatingly laminated. The second superlattice layer has a high electron reflectivity in an electron energy region where the electron reflectivity of the second first superlattice structure is low. Therefore, the high reflectivity of the second superlattice layer compensates for the low reflectivity of the first superlattice layer whereby a high electron reflectivity is maintained in the MQB structure.

Multiquantum barrier structure and semiconductor laser diode

A visible light laser diode includes an etching stopping layer having a lower etching rate in an etching solution than a cladding layer, having a larger band gap energy in bulk than the band gap energy of the active layer, including a layer that stops etching, and having a band gap energy exceeding an energy corresponding to the oscillation wavelength of the visible light laser diode. Therefore, the cladding layer can be selectively etched with satisfactory controllability to a predetermined shape. After the etching process, even with a laminated etching stopping layer partly remaining in the cladding layer, the etching stopping layer does not absorb light emitted from the active layer.

Visible light laser diode and manufacturing method of visible light

In a method for manufacturing a semiconductor laser diode, producing visible light after growing a p type GaAs contact layer on a p type AlGaInP cladding layer, an n type layer comprising that can be selectively etched with an etchant that does not etch GaAs is grown on the p type GaAs contact layer. After cooling, the n type layer is selectively etched and removed. In this method, a diffusion potential produced at the p-n junction between the p type GaAs contact layer and the n type layer prevents ionized hydrogen from entering the p type AlGaInP cladding layer during cooling, whereby the activation ratio of Zn atoms in the p type AlGaInP cladding layer is increased. Therefore, even if the Zn/III ratio during the growth of the p type AlGaInP cladding layer is low, a semiconductor laser diode with reduced threshold current and improved temperature characteristics is attained. In addition, since the n type layer grown on the p type GaAs contact layer comprises a semiconductor material that can be selectively etched with an etchant that does not etch GaAs, the etching process of the n type layer is carried out with high controllability without adversely affecting the surface of the p type GaAs contact layer, resulting in a highly reliable semiconductor laser diode.

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Itami, Japan

Kaoru Kadoiwa