Abstract
We have explored a different method to increase the phase switching speed for the nanocell of the non-volatile phase change random memories. The correlation between the nanocell size and the switching speed has been investigated theoretically, and the ultrafast phase switching has been demonstrated experimentally. The ultrafast switching mechanisms are discussed which are due to the contribution of free carriers and defects at the material interface when the cell dimension is sufficiently small. The nanoscaling effects of the phase change materials not only reduce the programming power, but also provide a new approach to enhance switching speed, which is highly essential for the realization of universal memory devices. (C) 2009 The Japan Society of Applied Physics