In this paper the experimental results of a study conducted to investigate dependence of low-frequency noise on the geometrical shape of VLSI interconnect are discussed. The metal thin films are most commonly used in fabrication of these metallic interconnects. The interconnection lines of modern ICs have effective cross sections in the range of 1-5 square μm. Therefore, the operating currents of a few milliamps results in current densities in the range of MA/square cm. Under these conditions, the phenomenon of electromigration arises, which may lead to the failure of the interconnection lines in a time ranging from a few several hours to several years, depending on the subjected current density J and thermal stress T. To study the effect of subjected current densities and temperatures, low-frequency noise measurements were performed on a group of ten metal thin film VLSI interconnects. These measurements were carried out under stressing current densities between 1.0x10<sup>5</sup> <i>A/cm<sup>2</sup></i> and 2.2 x10<sup>6</sup> <i>A/cm<sup>2</sup></i> at different heating temperatures up to 280 <sup>°</sup> C. We used a sophisticated noise measurement system based on dual-channel dynamic signal analyzer and ultra low-noise amplifier to monitor and capture the noise spectra exhibited by the samples when subjected to electrical and thermal stress. The low-frequency noise measurement system and measurement technique, metal thin film sample design, and the behavior of these samples under subjected stressing conditions are discussed in the paper.
In this paper the energy of an electron excited in conduction state in benzene (C<sub>6</sub>H<sub>6</sub>) molecule is estimated. The possible energy of the excited electron depends on the eigen energy state of the excited electron. Estimation of energy of an electron excited in conduction in C<sub>6</sub>H<sub>6</sub> molecule is necessary to analyze fluctuation in currents in benzene molecule. Stable current-voltage (I-V) behavior of benzene molecule ensures functionality of any nano device involving benzene molecule or its derivative. This theoretical work can be verified by experiment of radiation from an excited benzene molecule. The result will give precise idea about the energy needed to destabilize the electrical behavior of devices made of benzene molecules.
Benzene molecule is interseting for its potential in molecular nano electronics. The hexagonal core plane of the benzene molecule is relatively unalterable compared to the π localized electrons. Disturbance in the π-electron cloud will cause creation of hole by exciting a π electron to jump for conduction or may push an excited electron in the π electron cloud. The analysis of these effects rely on estimates of the energy imbalance due to presence of excited charged particles. This work is a beginning step in this front. The knowledge can be used to engineer improved switching mechanism using benzene molecule as an electronic device.