VLSI Design

https://www.hindawi.com/journals/vlsi/

List of Papers (Total 150)

Area Optimization of Slicing Floorplans in Parallel

We first present a parallel algorithm for finding the optimal implementations for the modules of a slicing floorplan that respects a given slicing tree. The algorithm runs in O(n) time and requires O(n) processors, where n is the number of modules. It is based on a new O(n2) sequential algorithm for solving the above problem. We then present a parallel algorithm for finding a set...

Input/Output Pad Placement Problem

We propose efficient heuristics for placing input/output (I/O) pads around the VLSI chip boundary. The heuristics are based on the circuit connectivity and do not require the placement of cells. This is useful for cell placement methods that require the knowledge of I/O pad placement. Using these heuristics, several pad placement candidates can be generated as input to cell...

Design and Implementation of a Low Power Ternary Full Adder

In this work, the design and implementation of a low power ternary full adder are presented in CMOS technology. In a ternary full adder design, the basic building blocks, the positive ternary inverter (PTI) and negative ternary inverter (NTI) are developed using a CMOS inverter and pass transistors. In designs of PTI and NTI, W/L ratios of transistors have been varied for their...

Lattice Effects in the Complex Subband Dispersion of 2DEG Semiconductor Waveguide Structures Subjected to a Perpendicular Magnetic Field

In modeling waveguide magneto-transport experiments (in a quasi-two dimensional electron gas), it is important to have knowledge of the electronic states in a magnetic field perpendicular to the plane of the waveguide confinement potential. We present numerical results, within a lattice model, for the full complex subband dispersion of a rectangular waveguide. The form of our...

Minimum Crosstalk Vertical Layer Assignment for Three-Layer VHV Channel Routing

With the increasing density of VLSI circuits, the interconnection wires are getting packed even closer. This has increased the effect of interaction between these wires on circuit performance and hence, the importance of controlling crosstalk. We consider the gridded channel routing problem where, specifically, the channel has 3 routing layers in the VHV configuration. Given a...

Temperature Dependence of the Electron and Hole Scattering Mechanisms in Silicon Analyzed through a Full-Band, Spherical-Harmonics Solution of the BTE

By adopting the solution method for the BTE based on the spherical-harmonics expansion (SHE) [1], and using the full-band structure for both the electron and valence band of silicon [2], the temperature dependence of a number of scattering mechanisms has been modeled and implemented into the code HARM performing the SHE solution. Comparisons with the experimental mobility data...

A Fast Algorithm for Performance-Driven Module Implementation Selection

We develop an O(p log n) time algorithm to obtain optimal solutions to the p-pin n-net single channel performance-driven implementation selection problem in which each module has at most two possible implementations (2-PDMIS). Although Her, Wang and Wong [1] have also developed an O(p log n) algorithm for this problem, experiments indicate that our algorithm is twice as fast on...

Building Rectangular Floorplans–A Graph Theoretical Approach

Rectangular dualisation is a technique used to generate rectangular topologies for use in top-down floorplanning of integrated circuits. In order for this technique to be used in a floorplanning system, its input, the connectivity graph representing an integrated circuit has to fulfill a number of conditions. This paper presents an efficient algorithm that transforms an arbitrary...

Distributed and Parallel Demand Driven Logic Simulation Algorithms

Based on the demand-driven approach, distributed and parallel simulation algorithms are proposed. Demand-driven simulation ties to minimize the number of component evaluations by restricting to only those component computations required for the watched output requests. For a specific output value request, the input line values that are required are requested to the respective...

New Methods for the Construction of Test Cases for Partitioning Heuristics

Partitioning is an important problem in the design automation of integrated circuits. This problem in many of its formulation is NP-Hard, and several heuristic methods have been proposed for its solution. To evaluate the effectiveness of the various partitioning heuristics, it is desirable to have test cases with known optimal solutions that are as “random looking” as possible...

A New Design Methodology for Two-Dimensional Logic Arrays

This paper introduces a new design approach that combines stages of logic and physical design. The logic function is synthesized and mapped to a two-dimensional array of logic cells. This array generalizes PLAs, XPLAs and cellular Maitra cascades. Each cell can be programmed to a wire, an inverter, or a two-input AND, OR or EXOR gate (with any subset of inputs negated). The gate...

High-Level Graphical Abstraction in Digital Design

We base our approach to the design of complex logic ICs on four premises:

Combining Technology Mapping With Layout

Due to the significant contribution of interconnect to the area and speed of today's circuits and the technological trend toward smaller and faster gates which will make the effects of interconnect even more substantial, interconnect optimization must be performed during all phases of the design. The premise of this paper is that by increasing the interaction between logic...

Quantum Kinetic Transport under High Electric Fields

Quantum kinetic transport under high electric fields is investigated with emphasis on the intracollisional field effect (ICFE) in low-dimensional structures. It is shown that the ICFE in GaAs one-dimensional quantum wires is already significant under moderate electric field strengths (≥ a few hundreds V/cm). This is a marked contrast to the cases in bulk, where the ICFE is...

Total Dielectric Function Approach to the Electron Boltzmann Equation for Scattering from a Two-Dimensional Coupled Mode System

The nonequilibrium total dielectric function lends itself to a simple and general method for calculating the inelastic collision term in the electron Boltzmann equation for scattering from a coupled mode system. Useful applications include scattering from plasmon-polar phonon hybrid modes in modulation doped semiconductor structures. This paper presents numerical methods for...

Cellular Automaton Study of Time-Dynamics of Avalanche Breakdown in IMPATT Diodes

Employing a recently developed efficient cellular automaton technique for solving Boltzmann’s transport equation for realistic devices, we present a detailed study of the carrier dynamics in GaAs avalanche p-i-n (IMPATT) diodes. We find that the impact ionization in reverse bias p-i-n diodes with ultrathin (less than 50 nm) intrinsic regions is triggered by Zener tunneling rather...

Monte Carlo Simulations of High Field Transport in Electroluminescent Devices

High field transport in phosphor materials is an essential element of thin film electroluminescent device performance. Due to the high accelerating fields in these structures (1–3 MV/cm), a complete description of transport under high field conditions utilizing information on the full band structure of the material is critical to understand the light emission process due to...

Shell-Filling Effects in Circular Quantum Dots

We investigate the dependence of the capacitive energy associated with a circular quantum dot on the number of electrons in the dot and on the parameters defining the potential confinement. Our results reproduce the shell-filling behavior that has recently been experimentally observed and allow us to estimate the shape of the confinement potential and the dot size of the...

Dynamic Cancellation: Selecting Time Warp Cancellation Strategies at Runtime

The performance of Time Warp parallel discrete event simulators can be affected by the cancellation strategy used to send anti-messages. Under aggressive cancellation, antimessage generation occurs immediately after a straggler message is detected. In contrast, lazy cancellation delays the sending of anti-messages until forward processing from a straggler message confirms that...

Electro-thermal Modelling of Monolithic and Hybrid Microwave and Millimeter Wave IC's

The first completely physical electro-thermal model is presented that is capable of describing the large signal performance of MESFET- and HEMT-based, high power microwave and millimeter wave monolithic and hybrid ICs, on timescales suitable for CAD. The model includes the effects of self-heating and mutual thermal interaction on active device performance with full treatment of...

Exact Output Response Computation of RC Interconnects Under General Polynomial Input Waveforms

Accurate output response computation of RC interconnects under various input excitations is a key issue in deep submicron delay analysis. In this paper, we present an exact analysis of output response computation of a distributed RC interconnect under input signals that are polynomial in time (tn). A simple, recursive equation that helps us to calculate the interconnect response...

Design and Analysis of Radix-8/4/2 64b/32b Integer Divider Using COMPASS Cell Library

A high speed 64b/32b integer divider employing digit-recurrence division method and the on-the-fly conversion algorithm, wherein a fast normalizer is included, which is used as the pre-processor of the proposed integer divider. For the sake of enhancing throughput rate, the proposed divider uses a mixed radix-8/4/2 division instead of the traditional radix-2 division. On-the-fly...

A Probabilistic Power Estimation Method for Combinational Circuits Under Real Gate Delay Model

Our aim is the development of a novel probabilistic method to estimate the power consumption of a combinational circuit under real gate delay model handling temporal, structural and input pattern dependencies. The chosen gate delay model allows handling both the functional and spurious transitions. It is proved that the switching activity evaluation problem assuming real gate...

Monte Carlo Calculations of Amplification Spectrum for GaN THz Transit-time Resonance Maser

We report Monte Carlo calculations of the amplification spectrum of microwave generation in bulk GaN and its dependence on applied electric fields, doping level, lattice temperature, etc. The amplification is shown to occur in a wide frequency range of 0.05 to 3 THz with an optimal generation efficiency of about 1 ∼ 2%.