Abstract: The present invention encompasses a method of selectively separating Ga from wastewaters with the aid of a dialysis method. This exploits the particular complexation behaviour of Ga, which forms an unstable tetrahalo complex. This forms only in the case of a sufficiently high halide concentration. Since the halide concentration becomes lower across the membrane, the Ga-tetrahalo complex breaks down in the membrane, as a result of which the Ga is retained. Other metals such as In and Fe do not show this behaviour, and therefore the tetrahalo complexes of these metals can pass through the membrane and hence can be selectively separated off.

Abstract: A device (1?, 1?, 1??) for manufacturing III-V-crystals and wafers (14) manufactured therefrom, which are free of residual stress and dislocations, from melt (16) of a raw material optionally supplemented by lattice hardening dopants comprises a crucible (2?, 2?, 2??) for receiving the melt (16) having a first section (4?, 4?) including a first cross-sectional area and a second section (6?) for receiving a seed crystal (12) and having a second cross-sectional area, wherein the second cross-sectional area is smaller than the first cross-sectional area and the first and second sections are connected with each other directly or via third section (8, 8?) which tapers from the first section towards the second section, in order to allow a crystallization starting from the seed crystal (12) within the directed temperature field (T) into the solidifying melt.

Abstract: A gallium arsenide substrate which exhibits at least one surface having a surface oxide layer comprising gallium and arsenic oxides and which exhibits at least one surface having, according to an ellipsometric lateral substrate mapping with an optical surface analyzer, based on a substrate diameter of 150 mm as reference, a defect number of <6000 and/or a total defect area of less than 2 cm2, wherein a defect is defined as a continuous area of greater than 1000 ?m2 having a deviation from the average measurement signal in elipsometric lateral substrate mapping with an optical surface analyzer of at least ±0.05%.

Abstract: The present invention relates to a novel provided gallium arsenide substrates as well as the use thereof. The gallium arsenide substrates provided according to the invention exhibit a so far not obtained surface quality, in particular a homogeneity of surface properties, which is detectable by means of optical surface analyzers, by way of example by means of ellipsometric lateral substrate mapping for optical contact-free quantitative characterization.

Abstract: The present invention relates to a novel process for producing a surface-treated gallium arsenide substrate as well as novel provided gallium arsenide substrates as such as well as the use thereof. The improvement of the process according to the invention is based on a particular final surface treatment with an oxidation treatment of at least one surface of the gallium arsenide substrate in dry condition by means of UV radiation and/or ozone gas, a contacting of the at least one surface of the gallium arsenide substrate with at least one liquid medium and a Marangoni drying of the gallium arsenide substrate. The gallium arsenide substrates provided according to the invention exhibit a so far not obtained surface quality, in particular a homogeneity of surface properties, which is detectable by means of optical surface analyzers, specifically by means of ellipsometric lateral substrate mapping for the optical contact-free quantitative characterization.

Abstract: The present invention encompasses a method of selectively separating Ga from wastewaters with the aid of a dialysis method. This exploits the particular complexation behaviour of Ga, which forms an unstable tetrahalo complex. This forms only in the case of a sufficiently high halide concentration. Since the halide concentration becomes lower across the membrane, the Ga-tetrahalo complex breaks down in the membrane, as a result of which the Ga is retained. Other metals such as In and Fe do not show this behaviour, and therefore the tetrahalo complexes of these metals can pass through the membrane and hence can be selectively separated off.

Abstract: The present invention relates to a novel provided gallium arsenide substrates as well as the use thereof. The gallium arsenide substrates provided according to the invention exhibit a so far not obtained surface quality, in particular a homogeneity of surface properties, which is detectable by means of optical surface analyzers, by way of example by means of ellipsometric lateral substrate mapping for optical contact-free quantitative characterization.

Abstract: A semiconductor compound material, preferably a III-N-bulk crystal or a III-N-layer, is manufactured in a reactor by means of hydride vapor phase epitaxy (HVPE), wherein in a mixture of carrier gases a flow profile represented by local mass flow rates is formed in the reactor. The mixture can carry one or more reaction gases towards a substrate. Thereby, a concentration of hydrogen important for the reaction and deposition of reaction gases is adjusted at the substrate surface independently from the flow profile simultaneously formed in the reactor.

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: The present invention relates to a novel process for producing a surface-treated gallium arsenide substrate as well as novel provided gallium arsenide substrates as such as well as the use thereof. The improvement of the process according to the invention is based on a particular final surface treatment with an oxidation treatment of at least one surface of the gallium arsenide substrate in dry condition by means of UV radiation and/or ozone gas, a contacting of the at least one surface of the gallium arsenide substrate with at least one liquid medium and a Marangoni drying of the gallium arsenide substrate. The gallium arsenide substrates provided according to the invention exhibit a so far not obtained surface quality, in particular a homogeneity of surface properties, which is detectable by means of optical surface analyzers, specifically by means of ellipsometric lateral substrate mapping for the optical contact-free quantitative characterization.

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 process and a device for producing crystalline silicon, particularly poly- or multi-crystalline silicon are described, wherein a melt of a silicon starting material is formed and the silicon melt is subsequently solidified in a directed orientation. A phase or a material is provided in gaseous, fluid or solid form above the melt in such a manner, that a concentration of a foreign atom selected from oxygen, carbon and nitrogen in the silicon melt and thus in the solidified crystalline silicon is controllable, and/or that a partial pressure of a gaseous component in a gas phase above the silicon melt is adjustable and/or controllable, the gaseous component being selected from oxygen gas, carbon gas and nitrogen gas and gaseous species containing at least one element selected from oxygen, carbon and nitrogen.

Abstract: A semiconductor compound material, preferably a III-N-bulk crystal or a III-N-layer, is manufactured in a reactor by means of hydride vapor phase epitaxy (HVPE), wherein in a mixture of carrier gases a flow profile represented by local mass flow rates is formed in the reactor. The mixture can carry one or more reaction gases towards a substrate. Thereby, a concentration of hydrogen important for the reaction and deposition of reaction gases is adjusted at the substrate surface independently from the flow profile simultaneously formed in the reactor.

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: In a process for manufacturing doped semiconductor single crystal comprises solidifying in a crucible, the amount of dopant is added into the semiconductor melt after the beginning of the crystal growth onto the seed crystal, or after at least partial solidification of the semiconductor single crystal in a conical or tapered portion of the crucible. Dopant may be partially added in advance into the crucible, with the remainder added into the semiconductor melt as described. Type III-V semiconductor single crystals or wafers having a diameter of at least about 100 mm, can be prepared having an electrical conductivity of at least about 250 Siemens/cm, and/or an electric resistivity of at most about 4×10?3 ?cm, and/or a significantly improved ratio of hall mobility to charge carrier concentration.

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 5×1017 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: A semiconductor compound material, preferably a III-N-bulk crystal or a III-N-layer, is manufactured in a reactor by means of hydride vapour phase epitaxy (HVPE), wherein in a mixture of carrier gases a flow profile represented by local mass flow rates is formed in the reactor. The mixture can carry one or more reaction gases towards a substrate. Thereby, a concentration of hydrogen important for the reaction and deposition of reaction gases is adjusted at the substrate surface independently from the flow profile simultaneously formed in the reactor.

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.