Structure investigation of large single crystals of gallium antimonide grown by the Czochralski method in the [100] direction

Abstract

Investigation of the properties of undoped single crystals of gallium antimonide with a diameter greater than 60 mm, grown by the Czochralski method in the crystallographic direction [100] has been carried out. We have found that a decrease in the dislocation density in bulk undoped single crystals of gallium antimonide can be achieved using conventional processing methods during the process of growing and by doping with isovalent indium impurities. It has been shown that the introduction of ageing for one hour in the process of manufacturing at a temperature close to the temperature of crystallization at the stage of the exit of the crystal to a given diameter, and further heat treatment in the postcrystallization state at a temperature of 650°C for three hours, allows one to reach the dislocation density value of (3–5) × 10³ cm^–2 in undoped single crystals of gallium antimonide with a diameter ~60 mm. It is established that the formation of a dislocation in large-sized single crystals of gallium antimonide is caused by two temperature ranges, as illustrated by the traces of dislocations with different morphology. The values of the critical stresses of the formation of a dislocation in the temperature range of 420–690°C are determined. It is shown that doping by isovalent impurities (In concentrations up to (2–4) × 10¹⁸ at/cm³) leads to a significant increase in the critical stress of the formation of a dislocation and, consequently, the reduction in their average density of up to (4–5) × 10² cm^–2. This opens up the prospect of obtaining large-sized single crystals of gallium antimonide with a small number of dislocations.