Structure and Kinetics in New Phase-Change and Ionic-Migration Memory Media

The current industry-standard technology for non-volatile memory is Flash, involving electrons trapped on the floating gate of a MOSFET. In the near future, no further size-reduction scaling of this will be possible due to technological limitations. Two new non-volatile memory technogies are being developed to replace Flash memory; i) phase-change (PC) media, in which there is a current-induced transformation between amorphous and crystalline states of a material, each having a different electrical resistance; ii) ion-migration or programmable metallization cell (PMC) technology, in which there is a voltage-induced growth of a conducting metallic filament in a solid electrolyte between two electrodes. In both cases, the large resistance changes between 'on' and 'off' states allow binary (and potentially even more, multilevel) data to be stored in a memory cell. The aim of this project is to gain a deep theoretical and experimental understanding of the physical and chemical processes involved in data recording in such memory media, and thereby to design, and synthesize, new memory media with much improved performance.