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Thermal Characterization of Advanced Material in Ultra-scaled Microelectronic Devices

Final Activity Report Summary - TCAMMD (Thermal characterisation of advanced material in ultra-scaled microelectronic devices)

Objective of the request for mobility
At the time of my request, the researcher was in charge of the research team "Thermocinetics and Characterisation" of the laboratory TREFLE (UMR 8508). The sphere of activity related to the thermal characterisation of materials and the non destructive thermal control (http://www.trefle.u-bordeaux1.fr).

The purpose of the request for mobility was to develop particular competences in the field of the characterisation of materials in the form of very thin layers, this characterisation relating to the thermal and structural properties of materials. It was desirable in addition to carry out this mobility in a European laboratory in order to discover new work methods and an environment different from the one the researcher was familiar with.

After having carried out a deepened research, contact was made with the MDM laboratory (Materials and devices for microelectronics) in Milan, Italy (http://www.mdm.infm.it/). This laboratory presented two important aspects with respect to the search criteria. It is first of all related to two important national structures: CNR (National Council of Research, are equivalent of CNRS in France) and the INFM (National Institute of the Physics of the Matter). In addition, this laboratory has the characteristic to be located within the STMicroelectronics company of Milan which is, with the site of Crolles in France, at the second place in the field of micro-electronics in Europe. The proposal of the laboratory was then to register the researcher in a European project 'Thermal characterisation of advanced materials in microelectronics devices' (TCAMMD) for his competences to be recognised in the field of thermal characterisation.

Research project
The purpose of the research project was to determine the thermal properties of a phase change material, candidate to be included in the next generation of non-volatile memory devices: Ge2Sb2Te5. In its amorphous state, this material is a semiconductor with high electrical resistivity. By increasing its temperature, its structure evolves to become crystalline and the material becomes a good conductor of electricity. Although this property had been highlighted since the years 1950, no particular attention was given to this material, due to the lack of potential applications at that time. Its use as active element in non-volatile memories (mobile telephony, storage of information...) appeared very recently and is still the source of an intense international competition nowadays. The major difficulty remains the integration of this material on terribly small scales about the hundred nanometers (1 nanometer=10^-9 m). One of the open questions related to this material integration is the knowledge of its thermal behaviour and of the other materials involved in the memory cell.