Diffusion of dopants in highly (∼1020cm−3) n- and p-doped GaSb-based materials

Diffusion of dopants at high doping concentrations (∼1020cm−3) of GaSb, GaInAsSb, and InAsSb grown in a molecular beam epitaxy system and doped with silicon, beryllium, and tellurium were investigated. The electrically active doping concentration for each material was determined by van der Pauw measurements, while the doping profiles were measured by secondary-ion-mass spectroscopy. The samples were annealed to analyze the diffusion behavior. Two different growth techniques to achieve high doping levels were compared: δ dopings and deposition with reduced growth rate. The diffusion of Be in InAsSb:Be could not be prevented, neither by a low growth rate nor by intermediate GaSb spacers. A strong diffusion of Be and Te was found for δ-doped samples in InAsSb, whereas in slowly grown material the diffusion can be limited for Te as dopant.