American Institute of Physics, Journal of Applied Physics, 10(104), p. 103712
DOI: 10.1063/1.3021462
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The aim of this article is to study the properties of the crystalline face centered cubic Ge 1 Sb 2 Te 4 phase as a function of annealing and measuring temperature. This material is one of the stoichiometric members of the Ge:Sb:Te family, which is widely used in the phase change data storage and one candidate for multistate recording. The electrical properties of this material have been investigated using two independent methods, the four probe impedance and the Hall measurements, and the results are interpreted in terms of structural parameters obtained from x-ray diffraction and transmission electron microscopy results. Experimental results have shown the polycrystalline nature of the film and that the transport properties have a strong dependence on the annealing temperature. An increase in the annealing temperature leads to an increase in the grain size, carrier concentration, mobility, and to a decrease in the volume fraction of grain boundaries. The mobility is limited by scattering of charge carries at the grain boundaries and can be described by a conduction model based on thermionic emission over the potential barriers. The large changes in the room temperature resistivity (more than 25 times) and effective capacitance (about 30%) of the polycrystalline state upon annealing due to various structural configurations increase (in addition to the amorphous in the crystalline transition) the dynamical range for multistate recording applications.