Floating Gate Nonvolatile Memory Using Individually Cladded Monodispersed Quantum Dots

Scaling down of cobalt quantum‐dots by colloidal route for non‐volatile memory device application

“…The process can further be optimised, and is potentially useful for the practical realisation of NVM devices. [5] thermal oxidation 7.4 SiO 2 (5.5 nm)/SiO 2 (13 nm) 1.9 V/±4 V Si [2] ball milling and chemical etching 6 SiO 2 (2 nm)/SiO 2 (7 nm) 0.5 V/±5 V Co [6] r e flux heating method 5 SiO 2 (4 nm)/Al 2 O 3 (10 nm) 8 V/±6 V Ni [3,14] microwave assisted synthesis 4 SiO 2 (4 nm)/Al 2 O 3 (10 nm) 1.3 V/±5 V Co [11] e-beam evaporation and thermal annealing 2 SiO 2 (3 nm)/HfO 2 (…”

QD floating gate NVRAM using QD channel for faster erasing

“…These nanocrystalline/QD flash memories were limited due to non-uniformity in the QD sizes and inter-dot spacing. Several efforts are ongoing to improve the performance of QD-based NVMs (QDNVMs) including the use of metallic nanocrystals [2] and the replacement of uncladded QDs with cladded QDs [3][4][5][6]. In this Letter, we present a device structure that transforms NVMs into nanosecond, low-power NVRAMs, by directly accessing the floating gate using the QD access channel (QDAC) via drain D2.…”

“…The drain D2 is 22 nm above the surface of source S and drain D1. The QDs were deposited using the site-specific selfassembly technique [5,6].…”

“…In (2), q is the charge of an electron, n dot is the number of electrons per dot (bound as well as the electrons trapped at the QDs interface), N QD is the density of QDs, and P w=>d is the tunnelling rate of carriers from the channel (quantum well) to QDs [6]. The amount of charges transferred to the QDs depends on the tunnelling probability of the wavefunctions of the inversion channel (ψ w ) and the QDs (ψ d ).…”

“…The amount of charges transferred to the QDs depends on the tunnelling probability of the wavefunctions of the inversion channel (ψ w ) and the QDs (ψ d ). The charges in a QD layer can be calculated by using the electron-tunnelling rate from the channel to the dots [5,6]. The electron distribution in an inversion channel/quantum well can be calculated by solving the 1D Schrödinger's and the Poisson's equations self-consistently.…”