ABSTRACT
New clathrate-based phase-change materials with cage-like structures incorporating Cs and Ba guest atoms, are reported as a means of altering crystallization and amorphization behavior by controlling 'guest-cage' interactions via intra-complex guest vibrational effects. Both a high resistance to spontaneous crystallization, and long retention of the amorphous phase are achieved, as well as a low melting energy. This approach provides a route for achieving cage-controlled semiconductor devices.
ABSTRACT
The quest for universal memory is driving the rapid development of memories with superior all-round capabilities in non-volatility, high speed, high endurance and low power. Phase-change materials are highly promising in this respect. However, their contradictory speed and stability properties present a key challenge towards this ambition. We reveal that as the device size decreases, the phase-change mechanism changes from the material inherent crystallization mechanism (either nucleation- or growth-dominated), to the hetero-crystallization mechanism, which resulted in a significant increase in PCRAM speeds. Reducing the grain size can further increase the speed of phase-change. Such grain size effect on speed becomes increasingly significant at smaller device sizes. Together with the nano-thermal and electrical effects, fast phase-change, good stability and high endurance can be achieved. These findings lead to a feasible solution to achieve a universal memory.
