Characteristic distributions of narrow channel metal-oxide-semiconductor field-effect transistor memories with silicon nanocrystal floating gates

We report the width and length dependences of threshold voltage shift and its distribution in narrow channel metal-oxide-semiconductor field-effect transistor (MOSFET) memories based on self-assembling silicon nanocrystals. As the channel width decreases, the threshold voltage shift, along with its distribution, increases. On the other hand, as the channel length decreases, the threshold voltage shift decreases. These results are well explained by the random distribution of silicon nanocrystals, in particular the number of dots on the narrow channel. The difference in width and length dependences is due to the difference in parallel and serial connections of unit cells. Based on the unit cell model, the width and length dependences of the threshold voltage shift are calculated and compared with the experimental results.