MANGANESE DIFFUSION IN MBE-GROWN CD(MN)TE STRUCTURES

The diffusion of Mn into CdTe films grown by molecular beam epitaxy (M BE) on (100)GaAs substrates was studied by secondary ion mass spectrom etry (SIMS). The samples were: 2 monolayer thick delta-MnTe embedded i n either semi-insulating or in indium-doped CdTe (N-In = 1 X 10(18) cm (-3)), and a 300 nm thick Cd0.75Mn0.25Te layer buried in undoped CdTe. Thermal annealing was performed in H-2 atmosphere at temperatures of 333-530 degrees C with samples covered face-to-face to avoid vaporizat ion, In the delta-MnTe samples the annealing caused symmetric spreadin g of the Mn marker in accordance with Fick's law. The activation energ y for diffusion of Mn in CdTe evaluated from the corresponding Arrheni us plot is E(d) = 1.35 eV irrespective of doping. The absolute value o f the Mn diffusivity in the In-doped CdTe is larger by a factor of 200 than that in the undoped layer. In layered CdTe/CdMnTe/CdTe structure s the Mn-Cd interdiffusion is associated with a higher activation ener gy than the diffusion of the diluted Mn solute. The intermixing is str ongly asymmetric, being much more pronounced at the interface closer t o the surface of the film.