Nanosecond-scale time-resolved electron imaging during laser crystallization of GeTe

Laser crystallization of amorphous phase change materials (PCMs) occurs on the nanosecond scale, during which it is challenging to probe the details of microstructural development experimentally. In this study, in situ laser-induced crystallization of amorphous GeTe thin films was imaged with transmission electron microscopy with 15-ns time resolution. These data provide insight into the crystallization process of PCMs during laser crystallization. The initial results allow us to begin to develop a detailed picture of the crystallization process when high spatial and temporal temperature gradients exist. Differences in the nucleation rate may be distinguished within the laser-affected area and changes in the microstructure before crystallization suggest the occurrence of melting of the amorphous phase at the laser energy used. The amorphous melting temperature is estimated based on the thermodynamic data available.