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: 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 III-V-, IV-IV- or II-VI-compound single crystal comprising III-, IV- or II-precipitates and/or unstoichiometrical III-V-, IV-VI-, or II-VI-inclusions, wherein concentration of the respective precipitates and/or inclusions is no more than 1×104 cm?3

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: A III-V-, IV-IV- or II-VI-compound single crystal comprising III-, IV- or II-precipitates and/or unstoichiometrical III-V-, IV-VI-, or II-VI-inclusions, wherein concentration of the respective precipitates and/or inclusions is no more than 1×104 cm?3

Abstract: The present invention relates to a process for the production of III-V-, IV-IV- or II-VI-compound semiconductor crystals. The process starts with providing of a substrate with optionally one crystal layer (buffer layer). Subsequently, a gas phase is provided, which comprises at least two reactants of the elements of the compound semiconductor (II, III, IV, V, VI) which are gaseous at a reaction temperature in the crystal growth reactor and can react with each other at the selected reactor conditions. The ratio of the concentrations of two of the reactants is adjusted such that the compound semiconductor crystal can crystallize from the gas phase, wherein the concentration is selected that high, that crystal formation is possible, wherein by an adding or adjusting of reducing agent and of co-reactant, the activity of the III-, IV- or II-compound in the gas phase is decreased, so that the growth rate of the crystals is lower compared to a state without co-reactant.

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: The present invention relates to a process for the production of III-V-, IV-IV- or II-VI-compound semiconductor crystals. The process starts with providing of a substrate with optionally one crystal layer (buffer layer). Subsequently, a gas phase is provided, which comprises at least two reactants of the elements of the compound semiconductor (II, III, IV, V, VI) which are gaseous at a reaction temperature in the crystal growth reactor and can react with each other at the selected reactor conditions. The ratio of the concentrations of two of the reactants is adjusted such that the compound semiconductor crystal can crystallize from the gas phase, wherein the concentration is selected that high, that crystal formation is possible, wherein by an adding or adjusting of reducing agent and of co-reactant, the activity of the III-, IV- or II-compound in the gas phase is decreased, so that the growth rate of the crystals is lower compared to a state without co-reactant.

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 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 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 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 device is made available for producing monocrystals, for example large-diameter gallium arsenide monocrystals, that has a cylindrical heating appliance with a floor heater (2) and a cover heater (3). The heating surfaces of the floor and the cover heater are considerably larger than the cross-sectional area of the monocrystal to be produced. In addition, an insulator (6) is planned for the reaction space that is designed to prevent a radial heat flow and the guarantee a strictly axial heat flow over the complete height of the reaction space between the cover heater (3) and the floor heater (2).