Determination of the isothermal nucleation and growth parameters for the crystallization of thin Ge2Sb2Te5 films

The isothermal crystallization of thin amorphous Ge2Sb2Te5 films, sandwiched between Si3N4 dielectric layers, was followed in real time using in situ transmission electron microscopy. A temperature-dependent incubation time is observed. After this incubation time, the crystallization is found to follow Johnson-Mehl-Avrami-Kolmogorov (JMAK) transformation kinetics. The JMAK parameters were determined, as well as the individual nucleation and growth parameters. The relationships between the JMAK parameters and the nucleation and growth parameters were tested and found to be valid. Nucleation was found to occur at the interfaces with the dielectric layers. The average grain size after crystallization did not show appreciable temperature dependence in the temperature range investigated. (C) 2002 American Institute of Physics.