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 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 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 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: The present invention relates to the use of diureides of dicarboxylic acids of the formula I in which R is hydrogen or SO2O⊖M⊕, M⊕ is lithium, sodium, potassium, cesium, ammonium, copper, silver, 0.5 iron, 0.5 calcium, 0.5 magnesium, 0.5 manganese, 0.5 zinc or 0.5 cobalt and X is a saturated or monounsaturated, straight-chain or branched C1- to C8-alkyl which may be interrupted by oxygen or NH and which may have attached to it C1- to C4-alkoxy, hydroxyl and/or amino groups, as slow-release fertilizers and to novel diureides of the formula Ia in which R is SO2O⊖M⊕, M⊕ is lithium, sodium, potassium, cesium, ammonium, copper, silver, 0.5 iron, 0.5 calcium, 0.5 magnesium, 0.5 manganese, 0.5 zinc or 0.5 cobalt and n is 1, 2, 3 or 4, and a process for their preparation.

Abstract: The present invention relates to the use of diureides of dicarboxylic acids of the formula I 1

Abstract: The present invention relates to the use of diureides of dicarboxylic acids of the formula I in which R is hydrogen or SO2OM⊕, M is lithium, sodium, potassium, cesium, ammonium, copper, silver, 0.5 iron, 0.5 calcium, 0.5 magnesium, 0.5 manganese, 0.5 zinc or 0.5 cobalt and X is a saturated or monounsaturated, straight-chain or branched C1-to C8-alkyl which may be interrupted by oxygen or NH and which may have attached to it C1-to C4-alkoxy, hydroxyl and/or amino groups, as slow-release fertilizers and to novel diureides of the formula Ia in which R is SO2OM⊕ M is lithium, sodium, potassium, cesium, ammonium, copper, silver, 0.5 iron, 0.5 calcium, 0.5 magnesium, 0.5 manganese, 0.5 zinc or 0.5 cobalt and n is 1,2,3 or 4, and a process for their preparation.