Abstract: A semiconductor device includes an AlGaN layer that is provided on a SiC substrate and has an acceptor concentration equal to or higher than a donor concentration, a GaN layer provided on the AlGaN layer, and an electron supply layer that is provided on the GaN layer and has a band gap greater than that of GaN.

Abstract: A semiconductor device includes a first GaN layer provided on a SiC substrate, a second GaN layer provided on the first GaN layer, and an electron supply layer that is provided on the second GaN layer and has a band gap greater than that of GaN, the first GaN layer having an acceptor concentration higher than that of the second GaN layer.

Abstract: A semiconductor substrate includes an AlN layer that is formed so as to contact a Si substrate and has an FWMH of a rocking curve of a (002) plane by x-ray diffraction, the FWMH being less than or equal to 1500 seconds, and a GaN-based semiconductor layer formed on the AlN layer.

Abstract: A HEMT comprised of nitride semiconductor materials is disclosed. The HEMT includes, on a SiC substrate, a AlN buffer layer, a GaN channel layer, and a AlGaN doped layer. A feature of the HEMT is that the AlN buffer layer is grown on an extraordinary condition of the pressure, and has a large unevenness in a thickness thereof to enhance the release of carriers captured in traps in the substrate back to the channel layer.

Abstract: A method for producing a nitride semiconductor device is disclosed. The method includes steps of: forming a channel layer, an InAlN doped layer sequentially on the substrate, raising a temperature of the substrate as supplying a gas source containing In, and/or another gas source containing Al, and growing GaN layer on the InAlN doped. Or, the method grows the channel layer, the InAlN layer, and another GaN layer sequentially on the substrate, raising the temperature of the substrate, and growing the GaN layer. These methods suppress the sublimation of InN from the InAlN layer.

Abstract: A method for fabricating a semiconductor device includes forming an AlN layer on a substrate made of silicon by supplying an Al source without supplying a N source and then supplying both the Al source and the N source, and forming a GaN-based semiconductor layer on the AlN layer after the forming of the AlN layer. The forming of the AlN layer grows the AlN layer so as to satisfy the following: 76500/x0.81<y<53800/x0.83 where x is a thickness of the AlN layer and y is an FWHM of a rocking curve of a (002) plane of the AlN layer.

Abstract: A method of manufacturing a semiconductor device includes growing a first GaN layer on a SiC substrate, and forming a second GaN layer on the first GaN layer, the second GaN layer being grown under such conditions that a ratio of a vertical growth rate to a horizontal growth rate is lower than that in the growth of the first GaN layer.

Abstract: A semiconductor device includes a first GaN layer formed on a substrate, the first GaN layer including a transition metal and an impurity under constant concentration, the impurity forming a deeper energy level in the first GaN layer than energy level formed by the transition metal, a second GaN layer formed on the first GaN layer, the second GaN layer including the transition metal and the impurity under inclined concentration, an inclined direction of the transition metal being same as an inclined direction of the impurity, and an electron supply layer formed on the second GaN layer.

Abstract: A semiconductor device includes a first GaN layer provided on a SIC substrate, a second GaN layer provided on the first GaN layer, and an electron supply layer that is provided on the second GaN layer and has a band gap greater than that of GaN, the first GaN layer having an acceptor concentration higher than that of the second GaN layer.

Abstract: A semiconductor device includes a silicon substrate; a buffer layer provided on the silicon substrate and has a band gap greater than GaN; a first GaN layer provided on the buffer layer; and a second GaN layer provided directly on the first GaN layer, a carbon concentration of the first GaN layer being higher than a carbon concentration of the second GaN layer.

Abstract: A semiconductor device includes an AlGaN layer that is provided on a SiC substrate and has an acceptor concentration equal to or higher than a donor concentration, a GaN layer provided on the AlGaN layer, and an electron supply layer that is provided on the GaN layer and has a band gap greater than that of GaN.

Abstract: A semiconductor substrate inclu8des an AlN layer that is formed so as to contact a Si substrate and has an FWMH of a rocking curve of a (002) plane by x-ray diffraction, the FWMH being less than or equal to 1500 seconds, and a GaN-based semiconductor layer formed on the AlN layer.

Abstract: A method for fabricating a semiconductor device includes forming an AlN layer on a substrate made of silicon by supplying an Al source without supplying a N source and then supplying both the Al source and the N source, and forming a GaN-based semiconductor layer on the AlN layer after the forming of the AlN layer. The forming of the AlN layer grows the AlN layer so as to satisfy the following: 76500/x0.81y<53800/x0.83 where x is a thickness of the AlN layer and y is an FWHM of a rocking curve of a (002) plane of the AlN layer.

Abstract: A semiconductor device includes a Si substrate having a principal plane that is a crystal surface inclined at an off angle of 0.1 degrees or less with respect to a (111) plane, an AlN layer that is provided so as to contact the principal plane of the Si substrate and is configured so that an FWHM of a rocking curve of a (002) plane by x-ray diffraction is not greater than 2000 seconds, and a GaN-based semiconductor layer formed on the AlN layer.

Abstract: A method for fabricating a semiconductor device includes performing thermal cleaning for a surface of a silicon substrate in an atmosphere including hydrogen under a condition that a thermal cleaning temperature is higher than or equal to 700° C. and is lower than or equal to 1060° C., and a thermal cleaning time is longer than or equal to 5 minutes and is shorter than or equal to 15 minutes; forming a first AlN layer on the substrate with a first V/III source ratio, the forming of the first AlN layer including supplying an Al source to the surface of the substrate without supplying a N source, and supplying both the Al source and the N source; forming a second AlN layer on the first AlN layer with a second V/III source ratio that is greater than the first ratio; and forming a GaN-based semiconductor layer on the second AlN layer.

Abstract: A method of manufacturing a light emitting diode includes forming an active layer of a nitride semiconductor on a first conductive type of a nitride semiconductor layer, thermally treating the active layer at a first temperature, and forming a second conductive type of a nitride semiconductor layer on the active layer at a second temperature lower than the first temperature.

Abstract: A semiconductor light emitting device includes a substrate and a quantum well active layer. The quantum well active layer has a plurality of barrier layers made of GaN-based semiconductor and a well layer made of GaN-based semiconductor sandwiched between the barrier layers and has polarized charge between the barrier layer and the well layer caused by piezo polarization. The well layer has a composition modulation so that a band gap is minimum at an interface between the well layer and one of the barrier layers more far from the substrate than the other.