The diffusion of Cd into GaAs single crystals was investigated at temperatures ranging from 804 to 1201C. The penetration profiles which were measured by using secondary ion mass spectroscopy and spreading-resistance profiling techniques were modelled numerically on the basis of the kick-out diffusion mechanism. This permitted estimates to be made of the Ga self-diffusivity, as mediated by doubly positively charged Ga self-interstitials, IGa2+. The Ga self-diffusivities which were found for As-rich and As-poor ambients were consistent. Under an As vapour pressure of 1atm, and under electronically intrinsic conditions, the IGa2+-mediated Ga self-diffusion data could be described by:

D (cm2/s) = 3.5 x 104 exp[-5.74(eV)/kT]

G.Bösker, N.A.Stolwijk, U.Södervall, W.Jäger: Defect and Diffusion Forum, 1997, 143-147, 1109-16

Table 15

Diffusivity of Ga Self-Interstitials in GaAs