The diffusion of Cr into epitaxial GaAs in an open system at 750 to 850C was studied. The temperature dependences of the diffusion coefficient (figure 19) and solubility of Cr were determined, and could be described by:

D (cm2/s) = 1.9 x 109 exp[-4.1(eV)/kT]

and

S (/cm3) = 2.3 x 1024 exp[-1.9(eV)/kT]

respectively. The effect of a protective SiO2 film upon the Cr diffusion coefficient and the morphology of the GaAs surface after diffusion was studied.

Diffusion of Chromium Into Epitaxial Gallium Arsenide. M.D.Vilisova, E.P.Drugova, I.V.Ponomarev, V.A.Chubirko: Semiconductors, 2008, 42[2], 238-41

Table 13

Diffusivity of Cr in GaAs