A. A. Orlikovsky

Measurement of dimensions of resist mask elements below 100 nm with help of a scanning electron microscope

We studied the effect of focusing of the electron probe of a scanning electron microscope (SEM), operating in the mode of collection of slow secondary electrons, on the form of a signal obtained when scanning elements of nanorelief of two kinds of objects with electron probe: (a) resist masks, and (b) protrusions and trenches on silicon. The shift of the positions of the points of reference, the distance between which is usually used to determine the size of the relief elements, was observed. The linear dependence of such distance on the size of the electron probe was found. We propose a method to measure the width of the nanorelief element, based on the extrapolation of this linear dependence to the zeroth size of the electron probe. With the help of this method, we measured the widths of nanorelief elements of resist masks, as well as of protrusions and trenches on silicon.

Effect of a transverse applied electric field on electron drift velocity in a GaAs quantum wire: A Monte Carlo simulation

A Monte Carlo simulation is run to study the electron transport in a thin undoped GaAs quantum wire under the influence of a transverse applied electric field. Phonon and surface-roughness scattering are included. Electron drift velocity is investigated as a function of roughness amplitude at a temperature of 77 or 300 K and a longitudinal electric field of 104 or 105 V/m. A transverse applied field is shown to provide a means of controlling drift velocity, affecting the scattering rate.

Aperture effect in plasma etching of deep silicon trenches

Abstract The aperture effect in plasma etching of deep trenches is theoretically investigated. Three possible mechanisms are proposed: limiting of ion and radical delivery to the etching region and redeposition of the reaction products. Integral equations are derived and numerically solved for rectangular trench profiles and a cosine law for surface scattering of the active particles. The approach suggested allows generalization for multicomponent plasma systems.

Fine-line plasma-enhanced processes on the basis of a set of pilot units with a scalable inductively coupled plasma source for use in microelectronics

An approach to the design of industrial-scale plasma processing techniques to meet the demands of modern micro-and nanoelectronics is discussed. Industrial plasma processing technology and equipment are considered as a single whole. This concept is implemented in a set of pilot plasma processing units based on a high-density plasma source. This set includes plasma etching, plasma-assisted dielectric deposition, and plasma immersion ion implantation units. The units are automated and equipped with in situ monitoring means.

New method for the Langmuir probe diagnostics of polymerizing plasmas

A pulsed Langmuir probe method of plasma diagnostics is proposed and validated for low-pressure, high-density, low-temperature plasmas capable of producing a nonconducting film on the probe surface. The method essentially involves cyclic probe-surface cleaning by ion bombardment. A switching pattern of probe potential is designed, taking into account the mechanism by which a space-charge region is formed near the probe. The method is successfully employed in an experiment on inductively coupled CHF3 and Ar plasmas. The results of the experiment are presented.

Computer Simulation of a Nanoscale Ballistic SOI MOSFET with a Sub-10-nm Si Layer

A physical model and a computer simulation program for nanoscale ballistic SOI MOSFETs are developed. The model includes transistor parameters such as the type and level of doping in the source and drain regions, gate length, Si and gate-oxide thicknesses, spacer length, gate-material work function, etc. Transistor performance is characterized in terms of transconductance, subthreshold slope, on- and off-state drain currents, gate–source overlap capacitance, etc. The software enables one to optimize the transistor parameters.

Comparative Study of an RF and a Microwave High-Density-Plasma Source for Plasma Immersion Ion Implantation

A comparative experimental study is conducted of an RF and a microwave plasma source placed in the same reactor, the RF source using inductive coupling. The conditions correspond to actual fabrication processes: the plasmas are excited in BF3 at pressures between 0.5 and 20 mtorr and at applied powers ranging from 400 to 1500 W. Local values and radial profiles are measured near the wafer by Langmuir-probe method for electron density and temperature and for the densities of positive and negative ions. The electron energy distribution function is determined. It is shown that the density of charged species in an RF plasma is considerably larger than in a microwave one; in particular, the ion density is as high as about 1012 cm–3 at an applied power of about 1200 W. The RF source is found to ensure adequate radial uniformity for wider ranges of external parameters. It is established that the two sources differ significantly from each other in electron energy distribution function. The BF3 plasmas are found to be electronegative, the ratio of negative- to positive-ion density lying in the range 0.3–0.5 for both sources.

Modeling of quantum noise and the quality of hardware components of quantum computers

In the present paper methods and algorithms of modeling quantum operations for quantum computer integrated circuits design are developed. The results of modeling of practically important quantum gates: controlled-NOT (CNOT), and controlled Z-transform (CZ) subject to different decoherence mechanisms are presented. These mechanisms include analysis of depolarizing quantum noise and processes of amplitude and phase relaxation.

Phase Formation in a Ta-Ni-N Thin Film during Its Electron-Beam Evaporation Deposition on a Heated Si(100) Substrate

Surface-diffusion reactions between a Ta–Ni–N alloy and a Si(100) substrate are studied experimentally. It is shown that a TaxSiyN/NiSi2bilayer can be produced on the substrate by simultaneous electron-beam evaporation of tantalum and nickel in a nitrogen atmosphere, the substrate being heated to about 800°C. The formation of the NiSi2 phase is examined.

Investigating the effect of amplitude and phase relaxation on the quality of quantum information technologies

In the formalism of quantum operations, we investigate the effect of the amplitude and phase relaxation on the evolution of quantum states. A model of the polarizing qubit, whose noises depend on the spectral degree of freedom that manifests itself in the process of light propagation in the anisotropic medium with dispersion, is discussed. An approximate analytical model is proposed for evaluating the effect of the phase plate on the polarizing state, taking into account the dispersion of light.