Abstract: According to one embodiment, a nitride semiconductor includes a base body, and a nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1?1), and a second nitride region including Alx2Ga1-x2N (0?x2<1, x2<x1). The first nitride region is between the base body and the second nitride region. The first nitride region includes a first portion and a second portion. The second portion is between the first portion and the second nitride region. An oxygen concentration in the first portion is higher than an oxygen concentration in the second portion. The oxygen concentration in the second portion is not more than 1×1018/cm3.A first thickness of the first portion in a first direction from the first to second nitride regions is thinner than a second thickness of the second portion in the first direction.

Abstract: According to one embodiment, a nitride structure includes a base, a nitride member including Ga and N, and a stacked structure provided between the base and the nitride member in a first direction. The stacked structure includes a plurality of high composition films including Alx1Ga1-x1N (0<x1?1), and a plurality of low composition films including Alx2Ga1-x2N (0?x2<1, x2<x1). A high composition film thickness of one high composition film is thinner than a nitride member thickness of the nitride member in the first direction. A low composition film thickness of one of the plurality of low composition films in the first direction is thinner than the nitride member thickness. The high composition film and the low composition film are provided alternately along the first direction. The plurality of high composition films includes a first film and another film.

Abstract: According to one embodiment, a nitride structure includes a stacked body. The stacked body includes a base including silicon, a first nitride region including AlN, and a second nitride region including Alz2Ga1-z2N (0?z2<1). The first nitride region is provided between the base and the second nitride region in a first direction. The stacked body includes a first interface region including a first interface between the base and the first nitride region. The first interface region includes a first peak position in the first direction. A chlorine concentration profile along the first direction in the stacked body has a chlorine peak value at the first peak position.

Abstract: According to one embodiment, a nitride semiconductor includes a base body, and a nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1?1), and a second nitride region including Alx2Ga1-x2N (0?x2<1, x2<x1). The first nitride region is between the base body and the second nitride region. The first nitride region includes a first portion and a second portion. The second portion is between the first portion and the second nitride region. An oxygen concentration in the first portion is higher than an oxygen concentration in the second portion. The oxygen concentration in the second portion is not more than 1×1018/cm3. A first thickness of the first portion in a first direction from the first to second nitride regions is thinner than a second thickness of the second portion in the first direction.

Abstract: According to one embodiment, a nitride semiconductor includes a base body, a nitride member, and an intermediate region provided between the base body and the nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1?1), and a second nitride region including Alx2Ga1-x2N (0?x2<1, x2<x1). The first nitride region is between the intermediate region and the second nitride region. The intermediate region includes nitrogen and carbon. A concentration of carbon in the intermediate region is not less than 1.5×1019/cm3 and not more than 6×1020/cm3.

Abstract: According to one embodiment, a wafer includes a silicon substrate, a first layer, and a plurality of structures. The first layer includes aluminum and nitrogen. The plurality of structures are provided between a part of the silicon substrate and a part of the first layer in a first direction from the silicon substrate to the first layer. The plurality of structures includes a first element and silicon. The first element includes at least one selected from the group consisting of Ni, Cu, Cr, Mn, Fe and Co. Another part of the first layer is in contact with another part of the silicon substrate.

Abstract: According to one embodiment, a nitride semiconductor includes a base body, a nitride member, and an intermediate region provided between the base body and the nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1?1), and a second nitride region including Alx2Ga1-x2N (0?x2<1, x2<x1). The first nitride region is between the intermediate region and the second nitride region. The intermediate region includes nitrogen and carbon. A concentration of carbon in the intermediate region is not less than 1.5×1019/cm3 and not more than 6×1020/cm3.

Abstract: According to one embodiment, a semiconductor structure includes a substrate including silicon crystal, a first layer including AlN crystal, and an intermediate region provided between the silicon crystal and the AlN crystal. The intermediate region includes Al and nitrogen. A direction from the silicon crystal to the AlN crystal is along a first direction. A third lattice plane spacing in the first direction of a lattice of Al atoms in the intermediate region is longer than a first lattice plane spacing in the first direction of the silicon crystal and longer than a second lattice plane spacing in the first direction of the AlN crystal.

Abstract: According to one embodiment, a nitride semiconductor includes a nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1?1), a second nitride region including Alx2Ga1-x2N (0<x2<1, x2<x1), and a third nitride region. The second nitride region is between the first nitride region and the third nitride region. The third nitride region includes Al, Ga, and N. The third nitride region does not include carbon, alternatively a third carbon concentration in the third nitride region is lower than a second carbon concentration in the second nitride region.

Abstract: According to one embodiment, a nitride semiconductor includes a nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1?1), a second nitride region including Alx2Ga1-x2N (0<x2<1, x2<x1), and a third nitride region. The second nitride region is between the first nitride region and the third nitride region. The third nitride region includes Al, Ga, and N. The third nitride region does not include carbon, alternately a third carbon concentration in the third nitride region is lower than a second carbon concentration in the second nitride region.

Abstract: According to one embodiment, a nitride semiconductor includes a nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N, a second nitride region including Alx2Ga1-x2N, and a third nitride region including Alx3Ga1-x3N. The second nitride region is provided between the first and third nitride regions in a first direction from the first nitride region to the second nitride region. The second nitride region includes carbon and oxygen. The first nitride region does not include carbon, or a second carbon concentration in the second nitride region is higher than a first carbon concentration in the first nitride region. The second carbon concentration is higher than a third carbon concentration in the third nitride region. A ratio of a second oxygen concentration in the second nitride region to the second carbon concentration is not less than 1.0 × 10-4 and not more than 1.4 × 10-3.

Abstract: According to one embodiment, a nitride semiconductor includes a nitride member. The nitride member includes a first nitride region including Alx1Ga1-×1N (0 < x1 ? 1), a second nitride region including Alx2Ga1-x2N (0 ? x2 < 1), and an intermediate region being between the first nitride region and the second nitride region. In a first direction from the first nitride region to the second nitride region, an oxygen concentration in the nitride member has a peak value at a first position included in the intermediate region. The peak value is 4.9 times or more a first oxygen concentration in the first nitride region. A second carbon concentration in the second nitride region is higher than a first carbon concentration in the first nitride region.

Abstract: A method for manufacturing a semiconductor device is provided, the method including forming an intermediate region including Alx3Ga1-x3N (0<x3?1 and x2<x3) on a first semiconductor layer including Alx1Ga1-x1N (0?x1<1); and forming a second semiconductor layer including Alx2In1-x2N (0<x2<1 and x1<x2) on the intermediate region, a first gas being used to form the intermediate region in the forming of the intermediate region, the first gas including a gas including Al, a gas including ammonia, and a gas including hydrogen, and a second gas being used to form the second semiconductor layer in the forming of the second semiconductor layer, the second gas including a gas including Al, a gas including In, a gas including ammonia, and a gas including nitrogen.

Abstract: According to one embodiment, a wafer includes a silicon substrate including a first surface, and a nitride semiconductor layer provided on the first surface. The silicon substrate includes a plurality of first regions that can be distinguished from each other in an X-ray image of the wafer. The first regions are separated from an outer edge region of the silicon substrate. One of the first regions includes a plurality of first linear bodies along a first line direction. An other one of the first regions includes a plurality of second linear bodies along a second line direction. The second line direction crosses the first line direction.

Abstract: According to one embodiment, a nitride semiconductor includes a base body including boron, a first nitride region including Alx1Ga1-x1N (0.98<x1?1), and a second nitride region including Alx2Ga1-x2N (0?x2<1, x2<x1). A concentration of boron in the base body is not less than 1×1019 cm?3. The first nitride region is between the base body and the second nitride region. The first nitride region includes a first surface facing the base body and a second surface facing the second nitride region. A second concentration of boron in the second surface is not more than 1/8000 of a first concentration of boron in the first surface.

Abstract: According to one embodiment, a nitride semiconductor includes a base body, a nitride member, and an intermediate region provided between the base body and the nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1?1), and a second nitride region including Alx2Ga1-x2N (0?x2<1, x2<x1). The first nitride region is between the intermediate region and the second nitride region. The intermediate region includes nitrogen and carbon. A concentration of carbon in the intermediate region is not less than 1.5×1019/cm3 and not more than 6×1020/cm3.

Abstract: According to one embodiment, a nitride semiconductor includes a base body, and a nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1?1), and a second nitride region including Alx2Ga1-x2N (0?x2<1, x2<x1). The first nitride region is between the base body and the second nitride region. The first nitride region includes a first portion and a second portion. The second portion is between the first portion and the second nitride region. An oxygen concentration in the first portion is higher than an oxygen concentration in the second portion. The oxygen concentration in the second portion is not more than 1×1018/cm3. A first thickness of the first portion in a first direction from the first to second nitride regions is thinner than a second thickness of the second portion in the first direction.

Abstract: A method for manufacturing a semiconductor device is provided, the method including forming an intermediate region including Alx3Ga1-x3N (0<x3?1 and x2<x3) on a first semiconductor layer including Alx1Ga1-x1N (0?x1<1); and forming a second semiconductor layer including Alx2In1-x2N (0<x2<1 and x1<x2) on the intermediate region, a first gas being used to form the intermediate region in the forming of the intermediate region, the first gas including a gas including Al, a gas including ammonia, and a gas including hydrogen, and a second gas being used to form the second semiconductor layer in the forming of the second semiconductor layer, the second gas including a gas including Al, a gas including In, a gas including ammonia, and a gas including nitrogen.

Abstract: According to one embodiment, a semiconductor device includes a first semiconductor layer including Alx1Ga1-x1N (0?x1<1), a second semiconductor layer including Alx2In1-x2N (0<x2<1 and x1<x2), and an intermediate region provided between the first and second semiconductor layers. The intermediate region includes Alx3Ga1-x3N (0<x3?1 and x2<x3). The second semiconductor layer includes first and second surfaces. The second surface is between the intermediate region and the first surface in a first direction. The first direction is from the first semiconductor layer toward the second semiconductor layer. The second semiconductor layer includes a plurality of first pits provided in the first surface. Widths of the first pits are 200 nm or more. A density in the first surface of the first pits is not less than 5×107/cm2 and not more than 1×108/cm2.

Abstract: According to one embodiment, a nitride semiconductor includes a nitride member including a first nitride region, a second nitride region, and a third nitride region. The second nitride region is between the first nitride region and the third nitride region in a first direction. A HAADF-STEM (High Angle Annular Dark-Field Scanning Transmission Electron Microscopy) image of the nitride member includes a plurality of bright points and a dark area between the bright points. The dark area is darker than the bright points. A third brightness of the dark area in a third image region corresponding to the third nitride region is lower than a first brightness of the dark area in a first image region corresponding to the first nitride region. A second brightness of the dark area in a second image region corresponding to the second nitride region is lower than the third brightness.