Quantum Dot Floating Gate Nonvolatile Random Access Memory Using Ge Quantum Dot Channel for Faster Erasing

This paper presents an approach to enhance floating gate quantum dot nonvolatile random access memory (QDNVRAM) cells in terms of higher-speed and lower-voltage Erase not possible with conventional floating gate nonvolatile memories. It is achieved by directly accessing the floating gate layer with a Ge quantum dot access channel via an additional drain (D2) during the Erase and/or Write operation. Quantum mechanical simulations in GeO_x-cladded Ge quantum dot layers functioning as the floating gate as well access channel to facilitate Erase and Write are presented. Experimental data on fabricated long channel nonvolatile random access memory cell with SiO_x-cladded Si dots is presented. Quantum simulations show lower voltage operation for GeO_x-cladded Ge QD floating gate than SiO_x-cladded Si dots. The Erase time is orders of magnitude faster than flash and is comparable to competing NVRAMs.