A Pearson Effective Potential for Monte-Carlo simulation of quantum confinement effects in various MOSFET architectures

A Pearson Effective Potential model for including quantization effects in the simulation of nanoscale nMOSFETs has been developed. This model, based on a realistic description of the function representing the non zero-size of the electron wave packet, has been used in a Monte-Carlo simulator for bulk, single gate SOI and double-gate SOI devices. In the case of SOI capacitors, the electron density has been computed for a large range of effective field (between 0.1 MV/cm and 1 MV/cm) and for various silicon film thicknesses (between 5 nm and 20 nm). A good agreement with the Schroedinger-Poisson results is obtained both on the total inversion charge and on the electron density profiles. The ability of an Effective Potential approach to accurately reproduce electrostatic quantum confinement effects is clearly demonstrated.Comment: 13 pages, 11 figures, 3 table

High-order accurate Lagrange-remap hydrodynamic schemes on staggered Cartesian grids

International audienceWe consider a class of staggered grid schemes for solving the 1D Euler equations in internal energy formulation. The proposed schemes are applicable to arbitrary equations of state and high-order accurate in both space and time on smooth flows. Adding a discretization of the kinetic energy equation, a high-order kinetic energy synchronization procedure is introduced, preserving globally total energy and enabling proper shock capturing. Extension to 2D Cartesian grids is done via C-type staggering and high-order dimensional splitting. Numerical results are provided up to 8th order accuracy

Simulation of surface engineering for ultra shallow junction formation of PMOS for the 90nm CMOS technology node and beyond

Abstract-Since the junctions in the most advanced CMOS devices are thinner and thinner, the influence of the surface of silicon is thus becoming significant on dopant diffusion. In this paper, based on experimental data, a methodology for calibration is proposed, taking this effect of surface into account. SIMS profiles are accurately fitted by simulation using a simple model of recombination of interstitials; the phenomenon of POED is well reproduced and validated by TCAD 1D simulations. Then, the impact of POED on the PMOS performances is quantified by anticipation with 2D TCAD simulations

Effective field and universal mobility in high-k metal gate UTBB-FDSOI devices

session 1: parameter extractionInternational audienceThis paper aims at reviewing experimental and theoretical behaviors of universal mobility in high-k metal gate UTBB-FDSOI devices. Based on split-CV mobility measurements, the parameter η, characterizing the effective field, has been extracted for a large range of back voltages and temperatures in devices with various equivalent oxide thicknesses. We demonstrated that a nearly universal trend for the mobility with respect to the effective field can be obtained in the front inversion regime but is difficult to obtain in the back channel inversion regime. Keywords—FDSOI, universal mobility, effective field, coefficient η

Diversity of innate immune cell subsets across spatial and temporal scales in an EAE mouse model

International audienceIn both multiple sclerosis and its model experimental autoimmune encephalomyelitis (EAE), the extent of resident microglia activation and infiltration of monocyte-derived cells to the CNS is positively correlated to tissue damage. To address the phenotype characterization of different cell subsets, their spatio-temporal distributions and contributions to disease development we induced EAE in Thy1-CFP//LysM-EGFP//CD11c-EYFP reporter mice. We combined high content flow cytometry, immunofluorescence and two-photon imaging in live mice and identified a stepwise program of inflammatory cells accumulation. First on day 10 after induction, EGFP+ neutrophils and monocytes invade the spinal cord parenchyma through the meninges rather than by extravasion. This event occurs just before axonal losses in the white matter. Once in the parenchyma, monocytes mature into EGFP+/EYFP+ monocyte-derived dendritic cells (moDCs) whose density is maximal on day 17 when the axonal degradation and clinical signs stabilize. Meanwhile, microglia is progressively activated in the grey matter and subsequently recruited to plaques to phagocyte axon debris. LysM-EGFP//CD11c-EYFP mice appear as a powerful tool to differentiate moDCs from macrophages and to study the dynamics of immune cell maturation and phenotypic evolution in EAE

Modeling Stressed MOS Oxides Using a Multiphonon-Assisted Quantum Approach—Part I: Impedance Analysis

Complementary MOS device electrical performances are considerably affected by the degradation of the oxide lay- ers and Si/SiO2 interfaces. A general expression for electrically stressed MOS impedance has been derived and applied within the nonradiative multiphonon theory of carrier capture/emission at oxide defects. The capacitance and the conductance of aged MOS field-effect transistor oxides, and their dependences on bias voltage, temperature, and stress conditions have been investigated

Modeling Stressed MOS Oxides Using a Multiphonon-Assisted Quantum Approach—Part II: Transient Effects

Multifrequency charge pumping analysis has been performed using a multiphonon-assisted charge trapping model in the view of analyzing the oxide region in energy and position that can be characterized using charge pumping (CP) characterization. Transient phenomena observed during CP and ac characterization (hysteresis loops) have been modeled, and the role of out-of- equilibrium quasi-Fermi levels in proximity of the Si/SiO2 inter- face has been studied in detail