Quantitative model for the kinetics of compositional intermixing in GaAs-AlGaAs quantum-confined heterostructures

A quantitative atomic-scale model for the kinetics of intermixing in GaAs-AlGaAs quantum-confined heterostructures is presented. The model takes into account the statistical nature of the defect diffusion through heterostructures and calculates its effect on the Ga-Al interdiffusion across the associated interfaces. The model has been validated by successfully predicting the observed amounts of bandgap shift induced by the process of hydrogen plasma induced defect layer intermixing, as well as for the process of impurity-free vacancy disordering using SiO/sub 2/ caps. Good agreement between calculated and measured bandgap shifts has been observed. Values of the group-III vacancy diffusion coefficient, where the agreement took place, are between 2 and 3/spl times/exp[-2.72/k/sub B/T] cm/sup 2//spl middot/s/sup -1/.