Abstract: 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—SiC(0001) having an off-angle of less than 5° as a main surface at a first temperature of 1480° C. or higher and 1530° 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.

Abstract: 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 ?m and no larger than 20 ?m. The recesses have a depth no smaller than 0.01 ?m and no larger than 0.1 ?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/cm2, and the epitaxial first single-crystal 4H-SiC layer has a defect density no larger than 2/cm2.

Abstract: 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.

Abstract: A method for manufacturing a single-crystal 4H—SiC substrate includes preparing a 4H—SiC bulk single-crystal substrate having a flat surface, and growing an epitaxial first single-crystal 4H—SiC layer having recesses on the 4H—SiC bulk single-crystal substrate to a thickness X, measured in micrometers (?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?3), and no larger than 10*X*10?3.

Abstract: A method for manufacturing a single-crystal 4H-SiC substrate includes preparing a 4H-SiC bulk single-crystal substrate having a flat surface, and growing an epitaxial first single-crystal 4H-SiC layer having recesses on the 4H-SiC bulk single-crystal substrate to a thickness X, measured in micrometers (?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?3), and no larger than 10*X*10?3.

Abstract: 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 ?m and no larger than 20 ?m. The recesses have a depth no smaller than 0.01 ?m and no larger than 0.1 ?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/cm2, and the epitaxial first single-crystal 4H-SiC layer has a defect density no larger than 2/cm2.

Abstract: 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 (?m), the recesses have a diameter Y (?m) no smaller than 0.2*X (?m) and no larger than 2*X (?m), and a depth of Z (nm) no smaller than (0.95*X (?m)+0.5 (nm)) and no larger than 10*X (?m).

Abstract: 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—SiC(0001) having an off-angle of less than 5° as a main surface at a first temperature of 1480° C. or higher and 1530° 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.

Abstract: 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 (?m), the recesses have a diameter Y (?m) no smaller than 0.2*X (?m) and no larger than 2*X (?m), and a depth of Z (nm) no smaller than (0.95*X (?m) +0.5 (nm)) and no larger than 10*X (?m).

Abstract: 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.

Abstract: A method of manufacturing a semiconductor device, includes introducing a substrate into a growth furnace, forming impurity absorption layers on the substrate and on inner walls of the growth furnace, the impurity absorption layers absorbing impurities on a surface of the substrate and impurities in the growth furnace, etching and removing the impurity absorption layers and a portion of the substrate to produce a thinned substrate, forming a buffer layer on the thinned substrate, and forming semiconductor layers on the buffer layer.

Abstract: A method of manufacturing a semiconductor laser includes sequentially forming a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer on top of one another on a semiconductor substrate; forming a ridge in the second conductivity type semiconductor layer; forming a first insulating film on the second conductivity type semiconductor layer at a first temperature; forming a second insulating film on the first insulating film at a second temperature, lower than the first temperature; and forming an electrode on the second insulating film.

Abstract: 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.

Abstract: 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 ? dpl (nm) is measured. A blue shift amount ? bl (nm) is defined as the difference between the wavelength ? apl (nm) 0f photoluminescence generated by application of pump light to the active layer on the one hand, and the wavelength ? dpl (nm) of photoluminescence from the window layer under pump light irradiation on the other hand. The blue shift amount ? bl is referenced during the fabrication process in order to predict catastrophic optical damage levels of semiconductor lasers.

Abstract: 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.

Abstract: In fabricating a semiconductor laser 10 with an oscillation wavelength of 770 to 810 nm, impurities are introduced into an MQW active layer 16 near a light emitting facet of the laser to form a disordered region constituting a window layer 20. Pumped light is applied to the window layer 20 to generate photo luminescence whose wavelength &lgr; dpl (nm) is measured. A blue shift amount &lgr; bl (nm) is defined as the difference between the wavelength &lgr; apl (nm) of photo luminescence generated by application of pumped light to the active layer 16 on the one hand, and the wavelength &lgr; dpl (nm) of photo luminescence from the window layer 20 under pumped light irradiation on the other hand. The blue shift amount &lgr; bl is referenced during the fabrication process in order to predict COD levels of semiconductor laser products.

Abstract: A heterojunction structure has an AlxGa1−xAs layer (0<x≦1), on which an AlyGa1−yAs layer (0≦y≦1 and y<x) is provided and having a band gap energy smaller than that of the AlxGa1−xAs layer and a valence band energy edge higher than that of the AlxGa1−xAs layer. When the AlyGa1−yAs layer is selectively etched, an Au electrode film is formed on a surface of the AlyGa1−yAs layer outside an etching region, a resist pattern is formed covering the Au electrode film and leaving exposed the etching region, and the AlyGa1−yAs layer is selectively removed by etching while irradiating with light, using an etching solution having a Fermi level higher than that of the AlyGa1−yAs layer.

Abstract: In a hetero junction structure having an AlxGa1−x As layer 10 (0<x≦1), on which an AlyGa1−yAs layer (0≦y≦1 and y<x) is provided as having a band gap smaller than that of the AlxGa1−xAs layer 10 and a valence band energy larger than that of the AlxGa1−xAs layer 10, when the AlyGa1−yAs layer is selectively etched, an Au electrode film 16 is formed on a surface of the AlyGa1−yAs layer outside an etching region 14, a resist pattern 18 is formed so as to cover the Au electrode film 16 and expose the etching region 14, and the AlyGa1−yAs layer is selectively removed through the mask of the resist pattern 18 under irradiation of light by use of an etching solution having a Fermi level higher than that of the AlyGa1−yAs layer.

Abstract: In fabricating a semiconductor laser 10 with an oscillation wavelength of 770 to 810 nm, impurities are introduced into an MQW active layer 16 near a light emitting facet of the laser to form a disordered region constituting a window layer 20. Pumped light is applied to the window layer 20 to generate photo luminescence whose wavelength &lgr; dpl (nm) is measured. A blue shift amount &lgr; bl (nm) is defined as the difference between the wavelength &lgr; apl (nm) of photo luminescence generated by application of pumped light to the active layer 16 on the one hand, and the wavelength &lgr; dpl (nm) of photo luminescence from the window layer 20 under pumped light irradiation on the other hand. The blue shift amount &lgr; bl is referenced during the fabrication process in order to predict COD levels of semiconductor laser products.

Abstract: 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:Ga.sub.x Al.sub.y In.sub.z N (I)wherein 0<x.ltoreq.1, 0.ltoreq.y<1, 0.ltoreq.z<1, and x+y+z=1. An aluminum nitride thin layer is interposed between neighboring pairs of gallium nitride selectively grown layers and has a composition expressed by the following chemical formula:Al.sub.x Ga.sub.1-x N (II)wherein 0.7<x.ltoreq.1.