The behavior of As which had been diffused into Hg1-xCdxTe (where x was between 0.19 and 0.23) from an ion-implanted source was studied by using secondary ion mass spectroscopy and transmission electron microscopy. It was found that the As redistributed during annealing via a multi-component mechanism in which the tail components differed, depending upon the etch-pit density of the material. A model was proposed which explained the existence of a surface retarded diffusion component, an atomic vacancy-based component in which As began on the Te sub-lattice, an atomic vacancy-based component in which the As began on a metal sub-lattice (and underwent diffusion which was enhanced by a chemical non-equilibrium that depended upon the etch-pit density), and a short-circuit component. The second of these components could be accurately described by a Gaussian solution to Fick's second law, with constant diffusion coefficients of about 3 x 10-14cm2/s at 400C and about 2 x 10-13cm2/s at 450C. The same model was applicable to diffusion from a grown source. No diffusion tails were found in metalorganic chemical vapor deposited material with etch-pit densities which were of the order of 106/cm2.

L.O.Bubulac, D.D.Edwall, C.R.Viswanathan: Journal of Vacuum Science and Technology B, 1991, 9[3], 1695-704

Figure 3

Diffusivity of Au in CdTe