Comparison of the Crystallization Behaviors in As-Deposited and Melt-Quenched N-Doped Ge2Sb2Te5 Thin Films

The crystallization behavior of nitrogen-doped Ge2Sb2Te5 (NGST) thin films was examined using a static laser heating method and transmission electron microscopy. Reflectance changes were examined, and the fraction of crystalline phase present was measured on a nanosecond time scale for various laser powers and duration times. A modified laser sequence was employed to determine the crystallization of the melt-quenched amorphous phase. Compared to an as-deposited NGST, the melt-quenched NGST showed a significantly faster crystallization with a shorter incubation time. The microstructures of the melt-quenched NGST systems demonstrated the presence of a number of fine crystalline grains upon crystallization, which is far different from the case of an as-deposited NGST. The findings indicate that the grain size is smaller in the crystallized NGST with a higher nitrogen content in the melt-quenched amorphous films. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3543927] All rights reserved.