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In this paper, work carried out in recent years at Coventry University on the diffusion of Hg in CdTe is reviewed, and where relevant, a comparison is made with other published work in the same material. CdTe is used extensively in the fabrication of IR devices using (Hg0.8Cd0.2)Te. The majority of the diffusion anneals were carried out in sealed silica capsules under saturated vapor pressure conditions due to Hg and the Hg concentration profiles were measured using a sectioning techniques. As is customary with II-VI materials, two component profiles were obtained in the majority of cases. It was found that the diffusion of Hg in CdTe is rate limiting volume diffusion involving a slow stream and a fast stream. From pressure dependency measurements it is proposed that the slow component occurs by an interstitial mechanism at low values of PHg and a vacancy mechanism at high values. In addition the diffusivity for the slow component increases systematically with etch pit density whereas the diffusivity for the fast component is independent of etch pit density. Both the Arrhenius plots of D and Co show a sharp change in gradient at 275 degrees C. When compared with the results reported by other workers there is considerable agreement, particularly at high temperatures, but at low temperatures there are distinct differences. The values of the Hg diffusivity in CdTe are independent of x in (HgxCd1-x)Te in the range 0 < x < 0.03 but is much less than for corresponding values in (Hg0.8Cd0.2)Te.
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