Browsing by Subject "Operating voltage"

Now showing 1 - 4 of 4

Open Access
2-nm laser-synthesized Si nanoparticles for low-power charge trapping memory devices
(IEEE, 2014-08) El-Atab, N.; Özcan, Ayşe; Alkış, Sabri; Okyay, Ali Kemal; Nayfeh, A.
In this work, the effect of embedding Silicon Nanoparticles (Si-NPs) in ZnO based charge trapping memory devices is studied. Si-NPs are fabricated by laser ablation of a silicon wafer in deionized water followed by sonication and filtration. The active layer of the memory was deposited by Atomic Layer Deposition (ALD) and spin coating technique was used to deliver the Si-NPs across the sample. The nanoparticles provided a good retention of charges (>10 years) in the memory cells and allowed for a large threshold voltage (Vt) shift (3.4 V) at reduced programming voltages (1 V). The addition of ZnO to the charge trapping media enhanced the electric field across the tunnel oxide and allowed for larger memory window at lower operating voltages. © 2014 IEEE.
Open Access
Low power Zinc-Oxide based charge trapping memory with embedded silicon nanoparticles
(ECS, 2014) Nayfeh, A.; Okyay, Ali Kemal; El-Atab, N.; Özcan, Ayşe; Alkış, Sabri
In this work, a bottom-gate charge trapping memory device with Zinc-Oxide (ZnO) channel and 2-nm Si nanoparticles (Si-NPs) embedded in ZnO charge trapping layer is demonstrated. The active layers of the memory device are deposited by atomic layer deposition (ALD) and the Si-NPs are deposited by spin coating. The Si-NPs memory exhibits a threshold voltage (Vt) shift of 6.3 V at an operating voltage of -10/10 V while 2.6 V Vt shift is obtained without nanoparticles confirming that the Si-NPs act as energy states within the bandgap of the ZnO layer. In addition, a 3.4 V Vt is achieved at a very low operating voltage of -1 V/1 V due to the charging of the Si-NPs through Poole-Frenkel emission mechanism at an electric field across the tunnel oxide E > 0.36 MV/cm. The results highlight a promising technology for future ultra-low power memory devices.
Open Access
Two-nanometer laser synthesized Si-nanoparticles for low power memory applications
(Springer International Publishing, 2016) El-Atab, N.; Okyay, Ali Kemal; Nayfeh, A.
Current flash memory devices are expected to face two major challenges in the near future: density and voltage scaling. The density of the memory is related to the gate length scaling which is constrained by the gate stack, namely, the tunnel oxide thickness. In fact, the gate length is required to be commensurate with the gate stack in order to maintain a good gate control and to avoid short channel effects. However, in conventional flash memories, the tunnel oxide thickness has a lower limit of 6-7 nm (depending on NOR or NAND structure) in order to avoid back-tunneling and thus leakage of charges which destroys the necessary retention characteristic of the memory (>10 years). The second problem which needs to be solved is the high program and erase operating voltages. Once again, the limitation to operating voltage scaling is the inability to reduce gate stack thickness. Therefore, it is imperative to find novel structures and materials to be incorporated in the memory cells which would allow tunnel oxide and voltage scaling. In this study, MOSFET- and MOSCAP-based memory devices are investigated along with the use of 2-nm silicon nanoparticles (Si-NPs) for charge storage. Atomic layer deposition is used to deposit the active layer of the memory and the spin coating is performed to deliver the Si-nanoparticles across the sample.
Open Access
ZnO based charge trapping memory with embedded nanoparticles
(IEEE, 2012) Rizk, A.; Oruç, Feyza B.; Okyay, Ali Kemal; Nayfeh, A.
A thin film ZnO charge trapping memory cell with embedded nanoparticles is demonstrated by Physics Based TCAD simulation. The results show 3V increase in the Vt shift due to the nanoparticles for the same operating voltage. In addition a 6V reduction in the programming voltage is obtained due the nanoparticles. In addition, the effect of the trapping layer and tunnel oxide scaling on the 10 year retention time is studied. © 2012 IEEE.