Abstract: A group III nitride film is formed on an epitaxial substrate having an underlayer film containing Al. According to the present invention, the change of the properties of the II nitride film may be reduced The properties of the semiconductor device may be thus reduced and the production yield may be improved. An underlayer 2 made of a group III nitride containing at least Al is formed on a substrate 1 made of a single crystal. An oxide film 3 is formed on the underlayer film 2 to produce an epitaxial substrate 10. The oxygen content of the oxide film 3 at the surface is not lower than 3 atomic percent and the thickness is not larger than 50 angstrom.

Abstract: A III nitride semiconductor substrate for ELO is provided for forming a III nitride film whose surface is controlled independent of the film's thickness. A III nitride underlayer including at least Al is directly formed on a base made of e.g. a sapphire single crystal, and not formed through a buffer layer formed at a low temperature. After that patterns made of e.g SiO2 are formed on the underlayer.

Abstract: A III nitride multilayer including a given substrate, a III nitride underfilm including an Al content of 50 atomic percent or more for all of the III elements present in the III nitride underfilm, and a III nitride film including a lower Al content than the Al content of the III nitride underfilm by 10 atomic percent or more. A full width at half maximum X-ray rocking curve value of the III nitride film is set to 800 seconds or below at the (100) plane. A full width at half maximum X-ray rocking curve value of the III nitride film is set to 200 seconds or below at the (002) plane.

Abstract: A substrate for epitaxial growth allowing formation of an Al-containing group III nitride film having high crystal quality is provided. A nitride film containing at least Al is formed on a 6H—SiC base by CVD at a temperature of at least 1100° C., for example. The substrate for epitaxial growth allowing formation of an Al-containing group III nitride film having high crystal quality is obtained by setting the dislocation density of the nitride film to not more than 1×1011/cm2, the full width at half maximum of an X-ray rocking curve for (002) plane to not more than 200 seconds and the full width at the half maximum of the X-ray rocking curve for (102) plane to not more than 1500 seconds.

Abstract: An acicular structure is formed of AlN on the main surface of a base made of single crystal. Then, a desired Al-including III nitride film is formed on the main surface of the base via the acicular structure.

Abstract: Plural island-shaped crystal portions are formed on a first Al-including nitride base. The island-shaped crystal portions are made of a second nitride, and have a nitride film including a third nitride epitaxially grown thereon. The island-shaped crystal portions function as nuclei during the growth of the third nitride-including film.

Abstract: A group III nitride film is formed on an epitaxial substrate having an underlayer film containing Al. According to the present invention, the change of the properties of the II nitride film may be reduced The properties of the semiconductor device may be thus reduced and the production yield may be improved. An underlayer 2 made of a group III nitride containing at least Al is formed on a substrate 1 made of a single crystal. An oxide film 3 is formed on the underlayer film 2 to produce an epitaxial substrate 10. The oxygen content of the oxide film 3 at the surface is not lower than 3 atomic percent and the thickness is not larger than 50 angstrom.

Abstract: The crystal orientation of the main surface of a sapphire single crystal base material to constitute an epitaxial substrate is inclined from the <0001> orientation (c-axis) preferably for the <1-100> orientation (m-axis) by a range within 0.02-0.3 degrees. Then, a surface nitride layer is formed at the main surface of the base material. Then, a III nitride underfilm is formed on the main surface of the base material via the surface nitride layer. The III nitride underfilm includes at least Al element, and the full width at half maximum at (101-2) reflection in X-ray rocking curve of the III nitride underfilm is 2000 seconds. The surface roughness Ra within 5 &mgr;m area is 3.5 Å.

Abstract: A semiconductor light-detecting element includes a given substrate, an underlayer and a light-detecting element structure which are formed on said substrate in turn. The underlayer is made of a nitride semiconductor including Al element with a dislocation density of 1011/cm2 or below. The light-detecting element structure is made of a nitride semiconductor layer group including Al element at a larger content than the nitride semiconductor making the underlayer with a dislocation density of 1010/cm2 or below.

Abstract: An acicular structure is formed of AlN on the main surface of a base made of single crystal. Then, a desired Al-including III nitride film is formed on the main surface of the base via the acicular structure.

Abstract: A III nitride semiconductor substrate for ELO is provided for forming a III nitride film whose surface is controlled independent of the film's thickness. A III nitride underlayer including at least Al is directly formed on a base made of e.g. a sapphire single crystal, not through a buffer layer formed at low temperature. After that, patterns made of e.g. SiO2 are formed on the underlayer.

Abstract: A III nitride multilayer including a given substrate, a III nitride underfilm including Al element of 50 atomic percentages or over for all of the II elements, and a III nitride film including Al element in lower Al content than the Al content of the III nitride underfilm by 10 atomic percentages or over. A full width at half maximum in X-ray rocking curve of the III nitride film is set to 800 seconds or below at (100) plane. A full width at half maximum in X-ray rocking curve of the III nitride film is set to 200 seconds or below at (002) plane.

Abstract: A semiconductor light-detecting element includes a given substrate, an underlayer and a light-detecting element structure which are formed on said substrate in turn. The underlayer is made of a nitride semiconductor including Al element with a dislocation density of 1011/cm2 or below. The light-detecting element structure is made of a nitride semiconductor layer group including Al element at a larger content than the nitride semiconductor making the underlayer with a dislocation density of 1010/cm2 or below.

Abstract: Plural island-shaped crystal portions are formed on a base. The island-shaped crystal portions are made of a second nitride, and the base is made of a first Al including nitride. Then, a nitride film made of a third nitride is epitaxially grown from the island-shaped crystal portions as nuclei.