R. Castro-Rodríguez^a and J.L. Peña^a,b

aApplied Physics Department, CINVESTAV-IPN, Mérida, C.P. 97310, Mérida, Yucatán México, ^bCICATA-IPN, Legaria 694 Col. Irrigación, México, D.F., C.P. 11500.

CdTe cluster was investigated during nucleation on a CdS substrate surface. Using atomic force microscopy (AFM) we have imaged particle coverage of CdTe cluster deposited by radio frequency magnetron sputtering (rf-sputtering), and a nucleation kinetcs model has been derived from an analysis of the particle size distribution observed by AFM. The reconstructed nucleation trend was characterized by a systematic behavior: the nucleation rate, negligible at the beginning, reaches a maximum after a certain time and tends to zero for longer deposition time. The nucleation process shows a temperature dependent incubation time. The incubation time is related to the time of formation of a "critical CdTe cluster". The size of the critical cluster is explained both by thermodynamic quantities and the amount of interface misfit strain energy of CdTe lattice with respect to substrate. The films were deposited at substrate temperature of 250, 300, 350 and 400°C respectively, the incubation time was calculated in 760.51, 502.2, 302.77 and 80.96 sec for each temperature respectively, and the activation energy that a CdTe atoms has to overcome to pass from the gas to the solid phase has been calculated in 0.43 eV.