Studies were made of self-diffusion and interdiffusion in buried Al71GaAs/ Al69GaAs/71GaAs and AlAs/71GaAs isotope heterostructures at temperatures of between 800 and 1160C. It was found that Ga diffusion at Al71GaAs/Al69GaAs interfaces decreased with increasing Al content. The Al-Ga interdiffusion at AlGaAs/GaAs and AlAs/GaAs interfaces revealed a concentration-dependent interdiffusion coefficient. The temperature dependence of Ga and Al diffusion in GaAs, and of Ga diffusion in AlGaAs, was described by a single activation enthalpy of the order of 3.6eV (table 9); but with different pre-exponential factors.
Self- and Interdiffusion in AlxGa1-xAs/GaAs Isotope Heterostructures H.Bracht, E.E.Haller, K.Eberl, M.Cardona: Applied Physics Letters, 1999, 74[1], 49-51
Table 9
Diffusivity of Al and Ga in AlxGa1-xAs
Diffusant | x | E (eV) | ln[Do(cm2/s)] |
Al | 0 | 3.50 | -1.77 |
Ga | 0 | 3.71 | -0.45 |
Ga | 0.41 | 3.70 | -1.05 |
Ga | 0.62 | 3.60 | -2.41 |
Ga | 0.68 | 3.51 | -3.96 |
Ga | 1.0 | 3.48 | -4.51 |