A thermodynamic calculation was presented which explained the origin of large stress fields, in and around Te precipitates, and the associated punching of dislocation loops in star-like patterns. The calculation was based upon the fact that stoichiometric deviations in Te-saturated crystals were accommodated by Te interstitials, Cd multivacancy complexes, and Te antisites. The Te interstitials were the most mobile of these, and dominated the precipitation process. When the precipitates first appeared, they were in droplet form. This form was modelled by using the Lennard-Jones 6-12 interaction potential. It was proposed that droplet growth occurred via 2 processes which operated in tandem. The first was the capture of excess Te interstitials to cause droplet over-pressurization. The second was the punching of interstitial dislocation loops whenever the pressure exceeded a threshold value. The flow of Te interstitials into the droplets was driven by the difference between their formation energies in the lattice and the free energy change of the droplets per Te atom which was added. It was shown that the possible droplet pressures far exceeded that which was required for loop punching and for sustaining the growth cycle.

R.D.S.Yadava, R.K.Bagai, W.N.Borle: Journal of Electronic Materials, 1992, 21[10], 1001-16