Heating Effects in Nanoscale Devices

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2D Monte Carlo Simulation of Hole and Electron Transport in Strained Si

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Quantum Transport Simulation of the DOS function, Self-Consistent Fields and Mobility in MOS Inversion Layers

We describe a simulation of the self-consistent fields and mobility in (100) Si-inversion layers for arbitrary inversion charge densities and temperatures. A nonequilibrium Green's functions formalism is employed for the state broadening and conductivity. The subband structure of the inversion layer electrons is calculated self-consistently by simultaneously solving the Schrödinger, Poisson and Dyson equations. The self-energy contributions from the various scattering mechanisms are calculated within the self-consistent Born approximation. Screening is treated within RPA. Simulation results suggest that the proposed theoretical model gives mobilities which are in excellent agreement with the experimental data

Monte Carlo simulation of hole transport in SiGe alloys

This paper employs Ensemble Monte Carlo method to simulate transport of holes in SiGe alloys. A three-band model was employed to describe the valence band of these alloys. The nonparabolicity and the warping effect of the heavy-hole and light-hole bands were considered in their dispersion relation, while the split-off band was described as parabolic and spherical. We consider phonon and alloy disorder scattering in these calculations. The mobility of holes for a range of SiGe al-loys was calculated at 300K. The simulation mobility results agree with the experimental data, implying that the selected transport model for holes in SiGe alloys is adequate

Feasibility, Accuracy and Performance of Contact Block Reduction method for multi-band simulations of ballistic quantum transport

Numerical utilities of the Contact Block Reduction (CBR) method in evaluating the retarded Green's function, are discussed for 3-D multi-band open systems that are represented by the atomic tight-binding (TB) and continuum k\cdotp (KP) band model. It is shown that the methodology to approximate solutions of open systems which has been already reported for the single-band effective mass model, cannot be directly used for atomic TB systems, since the use of a set of zincblende crystal grids makes the inter-coupling matrix be non-invertible. We derive and test an alternative with which the CBR method can be still practical in solving TB systems. This multi-band CBR method is validated by a proof of principles on small systems, and also shown to work excellent with the KP approach. Further detailed analysis on the accuracy, speed, and scalability on high performance computing clusters, is performed with respect to the reference results obtained by the state-of- the-art Recursive Green's Function and Wavefunction algorithm. This work shows that the CBR method could be particularly useful in calculating resonant tunneling features, but show a limited practicality in simulating field effect transistors (FETs) when the system is described with the atomic TB model. Coupled to the KP model, however, the utility of the CBR method can be extended to simulations of nanowire FETs.Comment: 10 Pages, 9 Figure

3-D TCAD Monte Carlo device simulator : state-of-the-art FinFET simulation

This work presents a comprehensive description of an in-house 3D Monte Carlo device simulator for physical mod-eling of FinFETs. The simulator was developed to consider var-iability effects properly and to be able to study deeply scaled devices operating in the ballistic and quasi-ballistic regimes. The impact of random dopants and trapped charges in the die-lectric is considered by treating electron-electron and electron-ion interactions in real-space. Metal gate granularity is in-cluded through the gate work functionvariation. The capability to evaluate these effects in nanometer3D devices makes the pre-sented simulator unique, thus advancing the state-of-the-art. The phonon scattering mechanisms, used to model the transport of electrons in puresilicon material system, were validated by comparing simulated drift velocities withavailable experi-mental data. The proper behavior of the device simulator is dis-played in a series of studies of the electric potentialin the device, the electron density, the carrier's energy and velocity, and the Id-Vg and Id-Vd curves

Angular Dependence of Solar Cell Parameters in Crystalline Silicon Solar Cells Textured with Periodic Array of Microholes

Surface texturing is an indispensable way of increasing absorption in solar cells. In order to properly characterize the effect of texturing, the angular dependence of the incidence light should be addressed. This is particularly important when the actual application where the incidence angle of the sunlight varies during the day is considered. This study presents the angular dependence of solar cell parameters in the case of periodically textured crystalline silicon (c-Si) solar cells with microholes. A standard solar cell with pyramid texturing is also studied for comparison. It is shown that the incidence angle for the highest efficiency depends on the surface structure. While a standard pyramid-textured surface performs best at the zero angle of incidence, it is needed to tilt the sample with microholes textures 15 degrees with respect to the surface normal. This is also confirmed by the simulation study performed for the structures presented in this study