Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Zempei Kawazu

Takanori Tanaka

Akihito Ohno

Nobuyuki Tomita

Kenichi Hamano

Yoichiro Mitani

Tatsuya Kimura

Norio Hayafuji

Diethard Marx

Tetsuya Yagi

Kazushige Kawasaki

Yuji Abe

Takeharu Kuroiwa

Katsuomi Shiozawa

Manabu Kato

Yutaka Mihashi

Toshiyuki Oishi

Takashi Motoda

Akihiro Shima

Yoshihiko Toyoda

Harumi Nishiguchi

Yasutomo Kajikawa

Akihiro Takami

Kaoru Kadoiwa

Akihito Ono

Naoyuki Kawabata

Yoshihisa Tashiro

Nariaki Fujii

Junji Ochi

A method for manufacturing a SiC epitaxial wafer includes: a first step of, by supplying a Si supply gas and a C supply gas, performing a first epitaxial growth on a SiC bulk substrate with a 4H&#x2014;SiC(0001) having an off-angle of less than 5&#xb0; as a main surface at a first temperature of 1480&#xb0; C. or higher and 1530&#xb0; C. or lower; a second step of stopping the supply of the Si supply gas and the C supply gas and increasing a temperature of the SiC bulk substrate from the first temperature to a second temperature; and a third step of, by supplying the Si supply gas and the C supply gas, performing a second epitaxial growth on the SiC bulk substrate having the temperature increased in the second step at the second temperature.

Method for manufacturing SiC epitaxial wafer

A single-crystal 4H-SiC substrate includes a 4H-SiC bulk single-crystal substrate; and an epitaxial first single-crystal 4H-SiC layer on the 4H-SiC bulk single-crystal substrate and having recesses. The recesses have a diameter no smaller than 2 &#x3bc;m and no larger than 20 &#x3bc;m. The recesses have a depth no smaller than 0.01 &#x3bc;m and no larger than 0.1 &#x3bc;m. A single-crystal 4H-SiC substrate also includes a 4H-SiC bulk single-crystal substrate; and an epitaxial first single-crystal 4H-SiC layer on the 4H-SiC bulk single-crystal substrate and having recesses. The density of the recesses in the epitaxial first single-crystal 4H-SiC layer is at least 10/cm, and the epitaxial first single-crystal 4H-SiC layer has a defect density no larger than 2/cm.

Single-crystal 4H-SiC substrate

A substrate support for supporting a substrate when forming a film on a surface of the substrate by chemical vapor deposition. The substrate support includes a graphite material having a recessed portion for accommodating the substrate, a multilayer film on the recessed portion and consisting of a first degassing prevention film of SiC and a sublimation prevention film of TaC or HfC stacked together, and a second degassing prevention film of SiC located on portions of the graphite material other than the recessed portion.

Substrate support and semiconductor manufacturing apparatus

A method for manufacturing a single-crystal 4H&#x2014;SiC substrate includes preparing a 4H&#x2014;SiC bulk single-crystal substrate having a flat surface, and growing an epitaxial first single-crystal 4H&#x2014;SiC layer having recesses on the 4H&#x2014;SiC bulk single-crystal substrate to a thickness X, measured in micrometers (&#x3bc;m). The recesses have a diameter Y, measured in micrometers, no smaller than 0.2*X and no larger than 2*X. In addition, the recesses have a depth Z, when measured in micrometers, no smaller than (0.95*X+0.5*10), and no larger than 10*X*10.

Method for manufacturing a single-crystal 4H&#x2014;SiC substrate

A method for manufacturing a single-crystal 4H-SiC substrate includes: preparing a flat 4H-SiC bulk single-crystal substrate; and epitaxially growing a first single-crystal 4H-SiC layer having recesses on the 4H-SiC bulk single-crystal substrate, wherein the first single-crystal 4H-SiC layer has a thickness of X (&#x3bc;m), the recesses have a diameter Y (&#x3bc;m) no smaller than 0.2*X (&#x3bc;m) and no larger than 2*X (&#x3bc;m), and a depth of Z (nm) no smaller than (0.95*X (&#x3bc;m)+0.5 (nm)) and no larger than 10*X (&#x3bc;m).

A nitride semiconductor device is manufactured by the step of forming a nitride semiconductor layer form on a GaN substrate main surface, the step of polishing a back surface of the GaN substrate formed with the above-mentioned nitride semiconductor layer, the step of dry etching the back surface of the GaN substrate subjected to the above-mentioned polishing by using a gas mixture of chlorine and oxygen, and the step of forming an n-type electrode on the back surface of the GaN substrate subjected to the above-mentioned dry etching.

Method of manufacturing nitride semiconductor device

In fabricating a semiconductor laser producing light with a wavelength of 770 to 810 nm, impurities are introduced into an MQW active layer near a light emitting facet of the laser to form a disordered region constituting a window layer. Pump light is applied to the window layer to generate photoluminescence whose wavelength &#x3bb; dpl (nm) is measured. A blue shift amount &#x3bb; bl (nm) is defined as the difference between the wavelength &#x3bb; apl (nm) 0f photoluminescence generated by application of pump light to the active layer on the one hand, and the wavelength &#x3bb; dpl (nm) of photoluminescence from the window layer under pump light irradiation on the other hand. The blue shift amount &#x3bb; bl is referenced during the fabrication process in order to predict catastrophic optical damage levels of semiconductor lasers.

Method of fabricating semiconductor laser

A heterojunction structure has an Al Ga As layer (0<x&lE;1), on which an Al Ga As layer (0&lE;y&lE;1 and y<x) is provided and having a band gap energy smaller than that of the Al Ga As layer and a valence band energy edge higher than that of the Al Ga As layer. When the Al Ga As layer is selectively etched, an Au electrode film is formed on a surface of the Al Ga As layer outside an etching region, a resist pattern is formed covering the Au electrode film and leaving exposed the etching region, and the Al Ga As layer is selectively removed by etching while irradiating with light, using an etching solution having a Fermi level higher than that of the Al Ga As layer.

Method for fabricating a semiconductor device

A high-quality gallium nitride layer is grown on a surface of a substrate which is exposed through a dielectric mask on the substrate. The high-quality gallium nitride layer has a composition expressed by the chemical formula:

Semiconductor device including Gallium nitride layer

A semiconductor device includes a GaAs substrate having a lattice constant; and a III-V mixed crystal semiconductor layer disposed on the GaAs substrate, containing Tl (thallium) and Ga (gallium) as Group III elements and As (arsenic) as a Group V element, and having a lattice constant larger than the lattice constant of the GaAs substrate. Therefore, the lattice mismatch of the III-V mixed crystal semiconductor layer with GaAs and the band gap energy of the III-V mixed crystal semiconductor layer are smaller than those of an InGaAs layer, resulting in a semiconductor device with improved operating characteristics and reliability.

Semiconductor device including T1 GaAs layer

A semiconductor light emitting device includes an Si substrate having opposed front and rear surfaces; an amorphous or polycrystalline first buffer layer disposed on the front surface of the Si substrate; and GaN series compound semiconductor layers successively disposed on the first buffer layer and including a light emitting region where light is produced by recombination of electrons and holes. In this light emitting device, since the Si substrate is cleavable, it is possible to produce resonator facets by cleaving. In addition, since the Si substrate is electrically conductive, a structure in which a pair of electrodes are respectively located on opposed upper and lower surfaces of the light emitting device is realized. Further, since the Si substrate is inexpensive, the light emitting device is obtained at low cost. Furthermore, since the amorphous or polycrystalline first buffer layer is disposed on the Si substrate, in the initial state of the growth of the GaN series compound semiconductor layers, plenty of growth nuclei are created, and the growth nuclei promote two-dimensional growth. As a result, high-quality GaN series compound semiconductor layers are obtained.

Semiconductor light emitting device

A semiconductor device includes an Si substrate, a stress absorbing layer of GaAs and disposed on the Si substrate, a buffer layer having a composition of Al.sub.x Ga.sub.1-x-y In.sub.y N (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1) and disposed on the stress absorbing layer, and a compound semiconductor layer having a composition of Al.sub.x Ga.sub.1-x-y In.sub.y N (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1) and disposed on the buffer layer. Therefore, the buffer layer protects the GaAs stress absorbing layer from high temperatures during the formation of the compound semiconductor layer, whereby the stress absorbing layer is prevented from decomposition. As a result, a stress due to lattice mismatch or thermal stress between the Si substrate and the compound semiconductor layer is absorbed in the GaAs stress absorbing layer having a lowest bulk modulus, whereby a compound semiconductor layer with reduced dislocations may be grown on the buffer layer and bending of the Si substrate prevented.

Heteroepitaxial semiconductor device including silicon substrate, GaAs

A method of fabricating a light emitting diode (LED) device producing visible light includes growing layers of an LED emitting blue light to form a blue LED; growing layers of an LED emitting green light to form a green LED; growing layers of an LED emitting red light to form a red LED; and uniting the three LEDs directly to each other by annealing. Therefore, an LED device that can emit light of all three colors from the same region of the LED device with variable light intensity is obtained.

Semiconductor light emitting diode producing visible light

A semiconductor laser includes an electrically insulating substrate having an opening; a first conductivity type first contact layer within the opening; a laminated semiconductor layer structure on the first contact layer and comprising a first cladding layer, an active layer, a second cladding layer, and a second contact layer wherein the first contact layer includes an aperture within the opening; a first electrode disposed on the electrically insulating substrate and extending to and contacting the first contact layer; and a second electrode in electrical contact with the second contact layer. The substrate is preferably sapphire, MgO, and spinel and the semiconductor layers are preferably GaN materials so that the laser emits short wavelength light. An electrode makes direct, reliable contact to the first cladding layer through an opening in the electrically insulating substrate without the need of mechanically working or etching the substrate.

Semiconductor laser producing short wavelength light

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.

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Tokyo, Japan

Zempei Kawazu