Non-volatile Si quantum memory with self-aligned doubly-stacked dots

We investigate a novel Si quantum memory, in which floating gates are self-aligned doubly stacked Si dots. It is experimentally shown that the self-aligned double dot memory shows excellent charge retention. The retention improvement is explained by a theoretical model considering quantum confinement and Coulomb blockade in the lower Si dot. It is also shown that charge retention is improved remarkably by lower dot size scaling without losing high-speed write/erase.