SIMS study of Al thermal diffusion in MBE-grown sandwiched-ZnSTe structures

Sandwiched structures that consist of ZnSTe/ZnSTe: Al/ZnSTe were fabricated by the molecular beam epitaxy technique on three GaAs substrates oriented along(100), (511) and (711), respectively, to study the thermal diffusion o f Al dopant in ZnS0.986Te0.014 matrix by secondary ion mass spectroscopy de pth profiling. The relative sensitivity factor of Al with respect to Zn was determined to be 4.5 +/- 0.5 x 10(19) cm(-3). The Al diffusion coefficient s at annealing temperature of 450 and 550 degrees C were found to be 2.1 x 10(-15) cm(2)/s and 2.1 x 10(-14) cm(2)/s, respectively, and the diffusion seems ro be isotropic, regardless of the crystallographic orientation. (C) 1999 Elsevier Science B.V. All rights reserved.