Thorough investigation of Si-nanocrystal memories with high-k interpoly dielectrics for sub-45nm node Flash NAND applications

In this paper we show for the 1st time that Silicon nanocrystal (Si-ncs) memories with high-k (HfO₂, Al₂O₃ and HfAlO) interpoly dielectrics (IPD) can offer excellent behaviour in the Fowler-Nordheim regime, with great relevance for future sub-45 nm NAND memory generations. We significantly advance the state-of-the-art by showing a strict correlation between the different IPD properties and the performance obtained on memory transistors down to 90 nm gate lengths. In particular the results demonstrate that HfAlO IPDs combine the fast p/e and good 105 cycles endurance behaviour of HfO₂ and the long retention of Al₂O₃ with no activation up to 125degC Then, in order to boost the memory window, we also integrated a hybrid Si-nc/SiN layer floating gate, with a HfAlO based IPD. It is shown that a 6V DeltaV_th can be achieved, with good retention and cycling behaviours.