Ab-initio Modeling of CBRAM Cells: from Ballistic Transport Properties to Electro-Thermal Effects

We present atomistic simulations of conductive bridging random access memory (CBRAM) cells from first-principles combining density-functional theory and the Non-equilibrium Green's Function formalism. Realistic device structures with an atomic-scale filament connecting two metallic contacts have been constructed. Their transport properties have been studied in the ballistic limit and in the presence of electron-phonon scattering, showing good agreement with experimental data. It has been found that the relocation of few atoms is sufficient to change the resistance of the CBRAM by 6 orders of magnitude, that the electron trajectories strongly depend on the filament morphology, and that self-heating does not affect the device performance at currents below 1 $\mu$A.Comment: 6 figures, conferenc

Ultralow‐Power Atomic‐Scale Tin Transistor with Gate Potential in Millivolt

After decades of continuous scaling, further advancement of complementary metal-oxide-semiconductor (CMOS) technology across the entire spectrum of computing applications is today limited by power dissipation, which scales with the square of the supply voltage. Here, an atomic-scale tin transistor is demonstrated to perform conductive switching between bistable configurations with on/off potentials ≤2.5 mV in magnitude. In addition to the low operation voltage, the channel length of the transistor is determined experimentally and with density-functional theory to be ≤1 nm because the atoms instead of electrons are information carriers in this device. The conductance at on-states of the bistable configurations varies between 1.2 G$_{0}$ to 197 G$_{0}$ (G$_{0}$ = 2e$^{2}$ h$^{-1}$, e stands for the electron charge and h for Planck\u27s constant). Thus, the device can supply driving current from 1 to ≈375 µA in magnitude for logic circuits with the drain-source dc voltage at decades of millivolts. The switching frequency of the atomic-scale tin transistor has reached 2047 Hz. Furthermore, the on/off potentials in millivolts can reduce the energy consumption in the interconnects of integrated circuits at least by ≈400 times. Therefore, the atomic-scale tin transistor has prospects in digital circuits with ultralow-power dissipation and can contribute to the sustainability of modern society

Detection or modulation at 35 Gbit/s with a standard CMOS-processed optical waveguide

Light modulation and detection within a single SOI waveguide is demonstrated at 1550 nm. Multi-functional devices allow simplified transceiver systems. Savings in the number of fabrication steps increase the yield and reduce costs