EU FP6 Projects on Memory Technologies

CHEMAPH

Chalcogenide-based phase change materials (which contain at least one element from Group VI in the periodic table: Te, Se, or S) have recently generated strong attention for electronic memory applications, due to their success as optical storage media. Phase change memories (PCM) are one of the most promising candidates for next-generation non-volatile memories, having the potential to improve the performance compared to Flash memories as well as to be scalable beyond Flash technology.

One technological issue is the phase-change layer deposition process, which principally determines the implementation of the material properties. Phase-change films are currently grown sputtering, a physical vapour deposition technique, which has yielded demonstrator chips. However, for continued down-scaling for high-density nanoelectronic devices and lower programming currents, greater control of film deposition over non-planar structures is than possible with sputtering is necessary. Despite this need, no other deposition routes are available nor widely studied

Abstract

The project therefore aims at the development of a film manufacturing process based on a chemical-based technique, metal-organic chemical vapor deposition (MOCVD). MOCVD enables the production of thin films with superior quality compared to those obtained by sputtering, especially in terms of conformality, converage and stoichiometry control, and allows implementation of phase-change films in nanoelectronic devices. The main phase-change chalcogenide material system that will be investigated is Ge2Sb2Te5 (GST), as it is already the basis of optica storage media and prototype PCM devices. This objective will require extensive studies of the thermochemical properties of a variety of possible precursor materials, and their interactions, and the investigation of the optimal process conditions to achieve desired film properties, such as resistivity, phase-transition temperature, roughness, density.

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