The Research Of GaSb Crystal Growth Process

GaSb is a direct band gap semiconductor material, whose band gap width is 0.725 eV, and lattice constant is 0.60959 nm. GaSb can match the lattice constant of III-V compound semiconductor materials, so the stress, defects and other issues caused by lattice mismatch are greatly reduced. GaSb has become an important substrate material for long wavelength LED, photoelectric detector and optical fiber communication devices.CZ method is usually used to prepare GaSb crystal. The advantage of CZ is crystal can be observed in each stage of growth, so adjusting the growth parameters is convenient. The disadvantage is GaSb melt surface is easily oxidized to formed scum, which hinders the process of seeding and growth; the micro defects may be produced in the growth process.In this paper, the researches on growth process of GaSb are carried out by LEC method. The study on basic theory of GaSb growth and the analyses of abnormal phenomena provide a theoretical basis for experimental design and the improvement of process. According to the physical properties of GaSb melt, suitable liquid sealant is selected to avoid the oxidation reaction of melt surface. By establishing the simulation model of GaSb growth and designing heater and insulation, the thermal field conducive to growth is obtained. With the overall optimization of seeding, shoulder growth, diameter growth, tail growth and the improvement of heat treatment, cutting, grinding and polishing, the 2 inch GaSb crystal wafers are produced. The influence factors, types and formation mechanism of GaSb defects are analysed. With the optimization of thermal field design, shoulder growth of small angle, control of solid-liquid interface, adjustment of stoichiometric ratio in GaSb polycrystalline materials, removal of impurities in GaSb polycrystalline materials and furnace, the micro defect in GaSb crystal is effectively reduced.