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 by 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.
The project therefore aims at the development of a film manufacturing process based on a chemical-based technique, metal-organic chemical vapour deposition (MOCVD). MOCVD enables the production of thin films with superior quality compared to those obtained by sputtering, especially in terms of conformality, coverage, 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). Once a suitable process is developed, it will be used to fabricate state-of-the-art memory cells at the 90/65 nm node, and the electrical performance compared with standard devices based on sputtered GST. Doping of GST and modified compounds will also be investigated to improve device performance.
Field of science
- /engineering and technology/materials engineering/coating and films
- /engineering and technology/nanotechnology/nanoelectronics
Funding SchemeSTREP - Specific Targeted Research Project
CH62 3QF Wirral Merseyside
20041 Agrate Brianza