ENHANCED SUPPRESSED INTERDIFFUSION OF INGAAS-GAAS-ALGAAS STRAINED LAYERS BY CONTROLLING IMPURITIES AND GALLIUM VACANCIES

The interdiffusion of In and Ga at an InGaAs-GaAs interface subjected to different annealing temperatures, times, and environments is demonstrated. The interdiffusion coefficients and activation energies are determined by correlating the shift in the photoluminescence peaks with the calculated quantum well transition energies based on an error function composition profile. The results indicate that a higher In composition In(x)Ga(1-x)GaAs single quantum well (SQW) leads to a higher interdiffusion coefficient of In and Ga in an As overpressure annealing condition. Also, As overpressure increases the interdiffusion, whereas Ga overpressure reduces the interdiffusion. The thermal activation energies for different In composition InGaAs-GaAs SQW's (x = 0.057, 0.10, 0.15) range from 3.3 to 2.6 eV for an As overpressure environment and from 3 to 2.23 eV for the Ga overpressure situation. With respect to impurity induced disordering by Zn using a Ga or As overpressure significantly effects the depth of the Zn diffusion front but significant mixing does occur in either case when the impurity front reaches the quantum well.