Abstract: To provide a nitride semiconductor single crystal substrate comprising a Si substrate and a nitride semiconductor film which has semi-polar (10-1m) plane (m: natural number) and a thickness of 1 ?m or more, the nitride semiconductor single crystal substrate being suitably used for a light-emitting device, the nitride semiconductor single crystal substrate being suitably used for a light-emitting device, this invention provides a nitride semiconductor single crystal substrate comprising a Si substrate having an off-cut angle of 1 to 35° in the <110> direction from the <100> direction, a buffer layer 2a (2b) made of at least one of SiC or BP formed on the Si substrate, a AlN buffer layer formed on the buffer layers, and a nitride semiconductor single crystal film formed on the AlN buffer layer, the nitride semiconductor single crystal film comprising any one of GaN (10-1m), AlN (10-1m), InN (10-1m) or a GaN (10-1m)/and AlN (10-1m) superlattice film.

Abstract: A back electrode 6 is formed in the back of a Si single crystal substrate 2 of a compound semiconductor in which an n-type 3C-SiC single crystal buffer layer 3 having a thickness of 0.05-2 ?m, a carrier concentration of 1016-1021/cm3, a hexagonal InwGaxAl1-w-xN single crystal buffer layer 4 (0?w<1, 0?x<1, w+x<1) having a thickness of 0.01-0.5 ?m, and an n-type hexagonal InyGazAl1-y-zN single crystal layer 5 (0?y<1, 0<z?1, y+z?1) having a thickness of 0.1-5 ?m and a carrier concentration of 1011-1016/cm3 are stacked in order on an n-type Si single crystal substrate top 2 having a crystal-plane orientation {111}, a carrier concentration of 1016-1021/cm3, and a surface electrode 7 is formed on a surface of a hexagonal InyGazAl1-y-zN single crystal layer 5, so as to provide a compound semiconductor device which causes little energy loss and allows an high efficiency and a high breakdown voltage.

Abstract: The present invention provides a nitride semiconductor single crystal including gallium nitride (GaN) or aluminum nitride (AlN) which are formed as a film to have good crystallinity without forming a 3C—SiC layer on a Si substrate, and which can be used suitably for a light emitting diode, a laser light emitting element, an electronic element that can be operated at a high speed and a high temperature, etc., as well as a high frequency device. A GaN (0001) or AlN (0001) single crystal film, or a super-lattice structure of GaN (0001) and AlN (0001) is formed on a Si (110) substrate via a 2H—AlN buffer layer.

Abstract: A substrate 1 for growing an electro-optical single crystal thin film in which two or more layers of buffer layers 3, 4, and 5 for buffering lattice mismatch between Si and BTO are formed on an Si (001) substrate 2 is provided as a substrate for growing an electro-optical single crystal thin film which can obtain an electro-optical single crystal thin film of BTO single crystal thin film 6 etc. with a large size and a very high quality.

Abstract: A substrate for compound semiconductor device and a compound semiconductor device using the substrate are provided which allow a breakdown voltage to be high, cause little energy loss, and are suitably used for a high-electron mobility transistor etc. An n-type 3C—SiC single crystal buffer layer 3 having a carrier concentration of 1016-1021/cm3, a hexagonal GaxAl1-xN single crystal buffer layer (0?x<1) 4, an n-type hexagonal GayAl1-yN single crystal layer (0.2?y?1) 5 having a carrier concentration of 1011-1016/cm3, and an n-type hexagonal GazAl1-zN single crystal carrier supply layer (0?z?0.8, and 0.2?y?z?1) 6 having a carrier concentration of 1011-1016/cm3 are stacked in order on an n-type Si single crystal substrate 2 having a crystal-plane orientation {111} and a carrier concentration of 1016-1021/cm3. A back electrode 7 is formed in the back of the above-mentioned substrate 2 and a surface electrode 8 is formed on a surface of the above-mentioned carrier supply layer 6.

Abstract: A back electrode 6 is formed in the back of a Si single crystal substrate 2 of a compound semiconductor in which an n-type 3C-SiC single crystal buffer layer 3 having a thickness of 0.05-2 ?m, a carrier concentration of 1016-1021/cm3, a hexagonal InwGaxAl1-w-xN single crystal buffer layer 4 (0?w<1, 0?x<1, w+x<1) having a thickness of 0.01-0.5 ?m, and an n-type hexagonal InyGazAl1-y-zN single crystal layer 5 (0?y<1, 0<z?1, y+z?1) having a thickness of 0.1-5 ?m and a carrier concentration of 1011-1016/cm3 are stacked in order on an n-type Si single crystal substrate top 2 having a crystal-plane orientation {111}, a carrier concentration of 1016-1021/cm3, and a surf ace electrode 7 is formed on a surface of a hexagonal InyGazAl1-y-zN single crystal layer 5, so as to provide a compound semiconductor device which causes little energy loss and allows an high efficiency and a high breakdown voltage.

Abstract: A substrate 1 for growing an electro-optical single crystal thin film in which two or more layers of buffer layers 3, 4, and 5 for buffering lattice mismatch between Si and BTO are formed on an Si (001) substrate 2 is provided as a substrate for growing an electro-optical single crystal thin film which can obtain an electro-optical single crystal thin film of BTO single crystal thin film 6 etc. with a large size and a very high quality.

Abstract: In a substrate for growth of a chemical compound semiconductor, at least on one surface of a Si single crystal substrate 2 with a thickness of 300 ?m, a porous Si single crystal 4 is formed. Pores of the porous Si single crystal 4 is opened outward. The surface of the porous Si single crystal 4 is covered by a 3C—SiC single crystal layer 3 with a thickness of 1 nm. The thickness of the porous Si single crystal 4 is, for example, 10 ?m.