Search results for "Non volatile memories"
showing 3 items of 3 documents
Effects of partial self-ordering of Si dots formed by chemical vapor deposition on the threshold voltage window distribution of Si nanocrystal memori…
2006
We study the role that the denuded zone around Si nanocrystals obtained by chemical vapor deposition plays on the fluctuations of the dot surface coverage. In fact, the capture mechanism of the silicon adatoms in the proximity of existing dots restricts the number of possible nucleation sites, the final dot size, and the dot position, thus driving the process toward partial self-order. We numerically evaluate the relative dispersion of surface coverage for several gate areas and compare the results to the fully random case. The coverage dispersion is related to the fluctuations from bit to bit of the threshold voltage window (Δ Vth) distribution of nanocrystal memories. The evaluations, com…
Memory cell structure integrated on semiconductor
2004
This invention relates to a memory cell Which comprises a capacitor having a ?rst electrode and a second electrode separated by a dielectric layer. Such dielectric layer com prises a layer of a semi-insulating material Which is fully enveloped by an insulating material and in Which an electric charge is permanently present or trapped therein. Such electric charge accumulated close to the ?rst or to the second electrode, depending on the electric ?eld betWeen the electrodes,therebyde?ningdifferentlogiclevels.
Distribution of the threshold voltage window in nanocrystal memories with Si dots formed by chemical vapor deposition: Effect of partial self-ordering
2004
Non volatile memories based on Si nanocrystals (Si-ncs) offer an important alternative to conventional floating gate devices, for the numerous potential advantages associated with the discrete-trap structures [1]. Isolated Si-ncs can be obtained by chemical vapor deposition (CVD) through a fully compatible CMOS process. So far, the main limitation for scaling the CVD Si-nc memories at sub-90 nm node is related to the expected fluctuation, from bit to bit, in the device threshold voltage (VTH), due to the spread in the sur- face fraction (Rdot) covered with Si dots [2]. The reason is the assumption that the dot position and the relative distance are fully random. It will be shown that the nu…