Abstract: A heteroepitaxial wafer comprises, in the following order: a silicon substrate having a diameter and a thickness; an AlN nucleation layer; a first strain building layer which is an AlzGal-zN layer having a first average Al content z, wherein 0<z; a first strain preserving block comprising ?5 and ?50 units of a first sequence of layers, the first sequence comprising an AlN layer and at least two AlGaN layers, and having a second average Al content y, wherein y a second strain building layer which is an AlxGal-xN layer having a third average Al content x, wherein 0?x<y; a second strain preserving block comprising ?5 and ?50 units of a second sequence of layers, the sequence comprising an AlN layer and at least one AlGaN layer, and having a fourth average Al content w, wherein x<w<y, and a GaN layer, wherein the layers between the AlN nucleation layer and the GaN layer form an AlGaN buffer.

Abstract: A heteroepitaxial wafer comprises, in the following order: a silicon substrate having a diameter and a thickness; an AlN nucleation layer; a first strain building layer which is an AlzGal-zN layer having a first average Al content z, wherein 0<z; a first strain preserving block comprising ?5 and ?50 units of a first sequence of layers, the first sequence comprising an AlN layer and at least two AlGaN layers, and having a second average Al content y, wherein y a second strain building layer which is an AlxGal-xN layer having a third average Al content x, wherein 0?x<y; a second strain preserving block comprising ?5 and ?50 units of a second sequence of layers, the sequence comprising an AlN layer and at least one AlGaN layer, and having a fourth average Al content w, wherein x<w<y, and a GaN layer, wherein the layers between the AlN nucleation layer and the GaN layer form an AlGaN buffer.

Abstract: Problems associated with the mismatch between a silicon substrate and a group-IIIA nitride layer are addressed by employing a silicon substrate processed to have a surface comprising closely spaced tips extending from the surface, depositing a group-IIIB silicide layer on the tips, then depositing a group-IIIB nitride layer, and then depositing a group-IIIA nitride.

Abstract: A layered semiconductor substrate has a monocrystalline first layer based on silicon, having a first thickness and a first lattice constant a1 determined by a first dopant element and a first dopant concentration, and in direct contact therewith, a monocrystalline second layer based on silicon, having a second thickness and a second lattice constant a2, determined by a second dopant element and a second dopant concentration, and a monocrystalline third layer comprising a group III nitride, the second layer located between the first layer and the third layer, wherein a2>a1, wherein the crystal lattice of the first layer and the second layer are lattice-matched, and wherein the bow of the layered semiconductor substrate is in the range from ?50 ?m to 50 ?m.

Abstract: A semiconductor wafer has a silicon single crystal substrate having a top surface and a stack of layers covering the top surface, the stack of layers containing an AlN nucleation layer covering the top surface of the silicon single crystal substrate, wherein the top surface of the silicon single crystal substrate has a crystal lattice orientation which is off-oriented with respect to the {111}-plane, the normal to the top surface being inclined with respect to the <111>-direction toward the <11-2>-direction by an angle ? of not less than 0.3° and not more than 6°, the azimuthal tolerance of the inclination being ±0.1°; and an AlGaN buffer layer which covers the AlN nucleation layer and contains one or more AlxGa1-xN layers, wherein 0<×<1.

Abstract: Problems associated with the mismatch between a silicon substrate and a group-IIIA nitride layer are addressed by employing a silicon substrate processed to have a surface comprising closely spaced tips extending from the surface, depositing a group-IIIB silicide layer on the tips, then depositing a group-IIIB nitride layer, and then depositing a group-IIIA nitride.

Abstract: A semiconductor wafer has a silicon single crystal substrate having a top surface and a stack of layers covering the top surface, the stack of layers containing an AlN nucleation layer covering the top surface of the silicon single crystal substrate, wherein the top surface of the silicon single crystal substrate has a crystal lattice orientation which is off-oriented with respect to the {111}-plane, the normal to the top surface being inclined with respect to the <111>-direction toward the <11-2>-direction by an angle ? of not less than 0.3° and not more than 6°, the azimuthal tolerance of the inclination being ±0.1°; and an AlGaN buffer layer which covers the AlN nucleation layer and contains one or more AlxGa1-xN layers, wherein 0<x<1.

Abstract: A semiconductor wafer contains the following layers in the given order: a monocrystalline substrate wafer (1) consisting predominantly of silicon and having a (111) surface orientation, a monocrystalline layer (3) of Sc2O3 having a (111) surface orientation, a monocrystalline layer (4) of ScN having a (111) surface orientation, and a monocrystalline layer (6) of AlzGa1-zN with 0?z?1 having a (0001) surface orientation, the semiconductor wafers are produced by appropriate deposition of the respective layers.

Abstract: A semiconductor wafer contains the following layers in the given order: a monocrystalline substrate wafer (1) consisting predominantly of silicon and having a (111) surface orientation, a monocrystalline layer (3) of Sc2O3 having a (111) surface orientation, a monocrystalline layer (4) of ScN having a (111) surface orientation, and a monocrystalline layer (6) of AlzGa1-zN with 0?z?1 having a (0001) surface orientation, the semiconductor wafers are produced by appropriate deposition of the respective layers.

Abstract: A layered semiconductor substrate has a monocrystalline first layer based on silicon, having a first thickness and a first lattice constant a1 determined by a first dopant element and a first dopant concentration, and in direct contact therewith, a monocrystalline second layer based on silicon, having a second thickness and a second lattice constant a2, determined by a second dopant element and a second dopant concentration, and a monocrystalline third layer comprising a group III nitride, the second layer located between the first layer and the third layer, wherein a2>a1, wherein the crystal lattice of the first layer and the second layer are lattice-matched, and wherein the bow of the layered semiconductor substrate is in the range from ?50 ?m to 50 ?m.