MICROSTRUCTURAL MEASUREMENTS OF AMORPHOUS GETE CRYSTALLIZATION BY HOT-STAGE OPTICAL MICROSCOPY

Time-resolved hot-stage transmission optical microscopy is used to characterize the nucleation and growth kinetics of amorphous GeTe thin-film crystallization. This technique provides experimental measurements of the fraction crystallized, the number of crystallites, and the crystallite size as a function of annealing time and temperature. The fraction-crystallized data are modelled using the Johnson-Mehl-Avrami formalism to give an Avrami exponent of 4, consistent with previous measurements via time-resolved reflection/ transmission methods. Microstructural measurements provide sufficient data to deconvolute the individual contributions of nucleation and growth to this exponent. This work shows that crystallization of these films proceeds by nucleation at an increasing rate due to transient effects with isotropic two-dimensional growth in the film plane. © 1995 American Institute of Physics.