Abstract: A process for producing a doped III-N bulk crystal, wherein III denotes at least one element of the main group III of the periodic system, selected from Al, Ga and In, wherein the doped crystalline III-N layer or the doped III-N bulk crystal is deposited on a substrate or template in a reactor, and wherein the feeding of at least one dopant into the reactor is carried out in admixture with at least one group III material. In this manner, III-N bulk crystals and III-N single crystal substrates separated therefrom can be obtained with a very homogeneous distribution of dopants in the growth direction as well as in the growth plane perpendicular thereto, a very homogeneous distribution of charge carriers and/or of the specific electric resistivity in the growth direction as well as in the growth plane perpendicular thereto, and a very good crystal quality.

Abstract: A single crystal having a technologically generated cleavage surface that extends along a natural crystallographic cleavage plane with an accuracy of less than |0.001°| when measured over a length relevant for the technology of the single crystal or over each of a plurality of surface areas extending in the direction of separation and having a length ?2 mm within the technologically relevant surface area.

Abstract: An arrangement for manufacturing a crystal of the melt of a raw material comprises: a furnace having a heating device with one or more heating elements, which are configured to generate a gradient temperature field directed along a first direction, a plurality of crucibles for receiving the melt, which are arranged within the gradient temperature field side by side, and a device for homogenizing the temperature field within a plane perpendicular to the first direction in the at least two crucibles. The arrangement further has a filling material inserted within a space between the crucibles wherein the filling shows an anisotropic heat conductivity. Additionally or alternatively, the arrangement may comprise a device for generating magnetic migration fields, both the filling material having the anisotropic heat conductivity and the device for generating magnetic migration fields being suited to compensate or prevent the formation of asymmetric phase interfaces upon freezing of the raw melt.

Abstract: An arrangement for manufacturing a crystal of the melt of a raw material comprises: a furnace having a heating device with one or more heating elements, which are configured to generate a gradient temperature field directed along a first direction, a plurality of crucibles for receiving the melt, which are arranged within the gradient temperature field side by side, and a device for homogenizing the temperature field within a plane perpendicular to the first direction in the at least two crucibles. The arrangement further has a filling material inserted within a space between the crucibles wherein the filling shows an anisotropic heat conductivity. Additionally or alternatively, the arrangement may comprise a device for generating magnetic migration fields, both the filling material having the anisotropic heat conductivity and the device for generating magnetic migration fields being suited to compensate or prevent the formation of asymmetric phase interfaces upon freezing of the raw melt.

Abstract: A process is disclosed for producing a doped gallium arsenide single crystal by melting a gallium arsenide starting material and subsequently solidifying the gallium arsenide melt, wherein the gallium arsenide melt contains an excess of gallium relative to the stoichiometric composition, and wherein it is provided for a boron concentration of at least 5×10?7 cm?3 in the melt or in the obtained crystal. The thus obtained crystal is characterized by a unique combination of low dislocation density, high conductivity and yet excellent, very low optic absorption, particularly in the range of the near infrared.

Abstract: The invention relates to a free-standing semiconductor substrate as well as a process and a mask layer for the manufacture of a free-standing semiconductor substrate, wherein the material for forming the mask layer consists at least partially of tungsten silicide nitride or tungsten silicide and wherein the semiconductor substrate self-separates from the starting substrate without further process steps.

Abstract: A device for evaporating a metal melt, the device comprising a first crucible or crucible portion operative to receive the metal melt comprising at least one aperture, from which the evaporated metal may pass off, a second crucible or crucible portion operative to receive a susceptor material, comprising an electromagnetic radiation source, which is arranged such that it can heat susceptor material comprised in the second crucible or crucible portion through incident electromagnetic induction, wherein it does not or only negligibly heats the metal melt in the first crucible or crucible portion, wherein the first crucible or crucible portion and the second crucible or crucible portion are thermally coupled, such that the metal melt can attain a desired temperature.

Abstract: A process for preparing smoothened III-N, in particular smoothened III-N substrate or III-N template, wherein III denotes at least one element of group III of the Periodic System, selected from Al, Ga and In, utilizes a smoothening agent comprising cubic boron nitride abrasive particles. The process provides large-sized III-N substrates or III-N templates having diameters of at least 40 mm, at a homogeneity of very low surface roughness over the whole substrate or wafer surface. In a mapping of the wafer surface with a white light interferometer, the standard deviation of the rms-values is 5% or lower, with a very good crystal quality at the surface or in surface-near regions, measurable, e.g., by means of rocking curve mappings and/or micro-Raman mappings.

Abstract: Bulk GaN and AlGaN single crystal boules, preferably fabricated using a modified HVPE process, are provided. The single crystal boules typically have a volume in excess of 4 cubic centimeters with a minimum dimension of approximately 1 centimeter. If desired, the bulk material can be doped during growth, for example to achieve n-, i-, or p-type conductivity.

Abstract: A process is disclosed for producing a doped gallium arsenide single crystal by melting a gallium arsenide starting material and subsequently solidifying the gallium arsenide melt, wherein the gallium arsenide melt contains an excess of gallium relative to the stoichiometric composition, and wherein it is provided for a boron concentration of at least 5×1017 cm?3 in the melt or in the obtained crystal. The thus obtained crystal is characterized by a unique combination of low dislocation density, high conductivity and yet excellent, very low optic absorption, particularly in the range of the near infrared.

Abstract: Method for producing a III-N (AlN, GaN, AlxGa(1-x)N) crystal by Vapor Phase Epitaxy (VPE), the method comprising: providing a reactor having: a growth zone for growing a III-N crystal; a substrate holder located in the growth zone that supports at least one substrate on which to grow the III-N crystal; a gas supply system that delivers growth material for growing the III-N crystal to the growth zone from an outlet of the gas supply system; and a heating element that controls temperature in the reactor; determining three growth sub-zones in the growth zone for which a crystal grown in the growth sub-zones has respectively a concave, flat or convex curvature; growing the III-N crystal on a substrate in a growth region for which the crystal has a by desired curvature.

Abstract: A method of dividing single crystals, particularly of plates of parts thereof, is proposed, which can comprise: pre-adjusting the crystallographic cleavage plane (2?) relative to the cleavage device, setting a tensional intensity (K) by means of tensional fields (3?, 4?), determining an energy release rate G(?) in dependence from a possible deflection angle (?) from the cleavage plane (2?) upon crack propagation, controlling the tensional fields (3?, 4?) such that the crack further propagates in the single crystal, wherein G(0)?2?e(0) and simultaneously at least one of the following conditions is satisfied: ? ? G ? ? ? ? = 0 ? 2 ? ? e h ? ? if ? ? ? 2 ? G ? ? 2 ? 0 ? ? or ( 2.1 ) ? ? G ? ? ? ? 2 ? ? e h ? ? ? ? : ? ? 1 < ? < ? 2 . ( 2.

Abstract: Method for producing a III-N (AlN, GaN, AlxGa(1-x)N) crystal by Vapor Phase Epitaxy (VPE), the method comprising: providing a reactor having: a growth zone for growing a III-N crystal; a substrate holder located in the growth zone that supports at least one substrate on which to grow the III-N crystal; a gas supply system that delivers growth material for growing the III-N crystal to the growth zone from an outlet of the gas supply system; and a heating element that controls temperature in the reactor; determining three growth sub-zones in the growth zone for which a crystal grown in the growth sub-zones has respectively a concave, flat or convex curvature; growing the III-N crystal on a substrate in a growth region for which the crystal has a by desired curvature.

Abstract: Bulk GaN and AlGaN single crystal boules, preferably fabricated using a modified HVPE process, are provided. The single crystal boules typically have a volume in excess of 4 cubic centimeters with a minimum dimension of approximately 1 centimeter. If desired, the bulk material can be doped during growth, for example to achieve n-, i-, or p-type conductivity.

Abstract: An embodiment of the invention provides a single crystal cleaved from a larger crystal and having a cleavage surface that extends along a natural crystallographic plane of the single crystal, the cleavage surface produced by generating a stress field to propagate a crack in the larger crystal along the natural plane, so that during cracking by the stress field a magnitude of a derivative of an energy release rate, G(?), generated by the stress field at a front of the crack as a function of angular deviation, ?, from the natural plane, is less than or equal to twice an effective step energy, ?e, divided by a step height, h.

Abstract: A method and a device for cutting a workpiece (1, 21) in a wire saw is described, wherein a workpiece (1, 21) is fixed in a wire saw by means of a mounting beam (2, 22). In the method according to the invention, the generation of a mark or a step on the cutting area along the cutting slit at the transition from the workpiece to the mounting beam (2, 22) is moved further to the edge of the cutting area or is avoided entirely. Therefore, the workpiece (1, 21) is held during the cutting operation in the wire saw by a mounting beam (2, 22) such that while one of the two piercing points (9; 29) lies on the surface of the workpiece (1, 21) and while simultaneously the other (10; 30) of the two piercing points (9, 10; 29, 30) lies on the surface of the mounting beam (2; 22), the piercing point lying on the surface of the workpiece is the entry side piercing point.

Abstract: Embodiments of the invention relate to a process for producing a III-N bulk crystal, wherein III denotes at least one element selected from group III of the periodic system, selected from Al, Ga and In, wherein the III-N bulk crystal is grown by vapor phase epitaxy on a substrate, and wherein the growth rate is measured in real-time. By actively measuring and controlling the growth rate in situ, i.e. during the epitaxial growth, the actual growth rate can be maintained essentially constant. In this manner, III-N bulk crystals and individualized III-N single crystal substrates separated therefrom, which respectively have excellent crystal quality both in the growth direction and in the growth plane perpendicular thereto, can be obtained.

Abstract: A device for heat treating (annealing) a III-V semiconductor wafer comprises at least one wafer support unit which is dimensioned such that a cover provided above the wafer surface is either spaced without any distance or with a distance of maximally about 2 mm to the wafer surface. A process for heat treating III-V semiconductor wafers having diameters larger than 100 mm and a dislocation density below 1×104 cm?2 is carried out in the device of the invention. SI GaAs wafers produced have an at least 25% increased characteristic fracture strength (Weibull distribution), an improved radial macroscopic and mesoscopic homogeneity and an improved quality of the mechano-chemically polished surface. The characteristic fracture strength is higher than 1900 MPa.

Abstract: A method of manufacturing a semipolar semiconductor crystal comprising a group-III-nitride (III-N), the method comprising: providing a substrate comprising sapphire (Al2O3) having a first surface that intersects c-planes of the sapphire; forming a plurality of trenches in the first surface, each trench having a wall whose surface is substantially parallel to a c-plane of the substrate; epitaxially growing a group-III-nitride (III-N) material in the trenches on the c-plane surfaces of their walls until the material overgrows the trenches to form a second planar surface, substantially parallel to a (20-2l) crystallographic plane of the group-III-nitride, wherein l is an integer.

Abstract: An epitaxial growth process for producing a thick III-N layer, wherein III denotes at least one element of group III of the periodic table of elements, is disclosed, wherein a thick III-N layer is deposited above a foreign substrate. The epitaxial growth process preferably is carried out by HVPE. The substrate can also be a template comprising the foreign substrate and at least one thin III-N intermediate layer. The surface quality is improved by providing a slight intentional misorientation of the substrate, and/or a reduction of the N/III ratio and/or the reactor pressure towards the end of the epitaxial growth process. Substrates and semiconductor devices with such improved III-N layers are also disclosed.