Annealing of Grown-in Defects in GaAs

Detailed analyses of positron lifetimes in GaAs have shown that an omnipresent type of defect acts as a shallow positron trap. This trap modifies the experimentally determined bulk lifetime to higher values and also influences the trapping rate into deep traps such as vacancies. It is suggested that the shallow trap likely is associated with boron. An annealing stage around 450°C is found.