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State of the art developments in silicon process and device technology other than VLSI are described and illustrated with reference to current work in the Northern Ireland Semiconductor Research Centre (NISRC). Applications discussed include power electronics and SMART power, fast bipolar heterojunction devices, large area electronics and sensors and actuators. Some of the specialised techniques used...
We have measured the CVV Auger spectra of Fe and S from FeS 2 and compared them, after deconvoluting, with results from other techniques and with band structure calculations. These Auger spectra exhibit a number of interesting features, including a strong feature similar to that found in metallic Fe, previously assigned to an 'autoionisation' process. The effective hole-hole interaction energy...
Voltage controlled negative differential resistance (NDR), electron emission (EE) and electroluminescence (EL) have been extensively studied for electroformed thin gold films deposited on glass substrates. The physical stability and the electrical significance of gold islands within the small, 1 μm, gap are not understood. The effect of treating the glass substrate with (3-Mercaptopropyl)trimethoxysilane...
Hydrogen depth profiles in the surface region of the metals Au, Ag, Cu and some characteristics are studied by ERDA. The structures of hydrogen depth distributions in these metal surfaces are similar, a layer of surface adsorption, diffusion depth and a hydrogen-containing matrix are obvious and some of the differences between them are discussed. The results show that the method is valuable for the...
The aim of this paper is the investigation of a GeSi/Si heterostructure formation obtained by deposition of Ge and Si layers of different thickness. Ge x Si 1-x /Si films obtained by MBE in high vacuum were multilayered systems with alternate Si and Ge layers. The layer thickness was 10-150 a. The samples were obtained at substrate temperatures from RT to 700 o C...
This paper presents an exhaustive review of trends in the development of methods for calibration of vacuum gauges in which pressure-time dependences are used. The author proposes and describes techniques for improving the calibration, the main objective of which is to extend the range of pressure measurements, to increase their accuracy and to raise the productivity of calibration (by reducing the...
The stoichiometry of a-SiN x :H films is determined by conventional elastic recoil detection analysis (ERDA) using 90 MeV i 58 Ni ions. Hydrogen depth profiling indicated that the non-uniformity in H concentration across the film thickness is about 12%. The present experiment indicated the capability of conventional ERDA for simultaneous multi-element detection in a thin film...
A new technique to determine the optical constants and band gaps of a bilayer semiconductor film is described. The theory and the technique have been successfully applied to determine the optical parameters of individual layers for three bilayered semiconductor systems: CdS/CdTe, CdS/CuInSe 2 and ZnS/ZnSe.
Microscopic contaminants occurring in the semiconductor manufacturing environment have been analysed using SAXPS. The molecular information obtained can be utilised to successfully identify and locate the sources of contamination. A description of the working principles of SAXPS and case studies in wafer fabrication and packaging assembly are presented.
The angular distribution of sputtered atoms and the surface topography of cadmium bombarded by 27 KeV Ar + ions were studied using Rutherford Backscattering Spectroscopy (RBS) and Scanning Electron Microscopy (SEM) analysis. It is shown that the variation of both distribution shapes and topographic features is found to be sensitive to the dose of incident ions and the relationship between...
An optical technique is proposed to determine the surface roughness and grain diameter for films having columnar grains and deposited onto nonabsorbing substrates.
Titanium nitride films were prepared on glass substrates by dc reactive magnetron sputtering from a titanium metal target in an Ar+N 2 mixed atmosphere. During deposition, the total pressure was varied from 2 10 -3 to 3 10 -2 mbar. The effects of the total pressure on the structural, optical and electrical properties of the films were studied using X-ray diffraction,...
The spectroscopic and Langmuir probe characteristics of a low pressure argon glow discharge plasma were studied and the electron temperature (T e ) was measured independently by both methods. The experiments were carried out in a SS 304 uhv chamber used for studying glow discharge cleaning techniques. Two types of excitation sources, dc and rf, were used. The Corona model was used to evaluate...
A saddle field cold cathode source was used to produce diamond-like carbon (DLC) coatings on glass substrates by dissociation and ionisation of acetylene in a low pressure vacuum. Langmuir probe investigations of the ion current density and plasma potentials showed the existence of a positive potential barrier at a distance of 100 mm from the source with an ionisation degree of up to 80% in the carbon...
A comprehensive description of the broadening of the absorption tail in polycrystalline semiconductor films has been presented by considering intrinsic inhomogeneity due to random distribution of grains and grain boundary regions and the fluctuation in potential from local thermal vibrations present at the grains and grain-grain interfaces. The model has been applied to describe the absorption data...
We have investigated isotope effects in the sputtering of a u 63 Cu 69.165 Cu 30.9 mixture under 2 keV Xe ion bombardment, using a dynamic Monte Carlo program. For the u- 63 Cu- 65 Cu sputtering, our calculations show that the isotope fractionation difference between small and large polar angles, δ(15 ...
During titanium layer deposition with a hollow cathode arc discharge, the integral energy influx to the substrate has been monitored by measuring temperature gradients. Discharge power and substrate voltage have been varied. Simultaneously, the plasma parameters in front of the substrate were determined by means of Langmuir-probe measurements and energy resolved mass spectrometry (plasma monitoring)...
1 6 O ions at 75 MeV incident energy have been used to study the irradiation effects on the normal state resistance variation with fluence. The studies conducted include the measurement of resistance variation with dose due to the ion used. The samples were the bulk sintered pellets of YBa 2 Cu 3 O 7-x maintained at normal temperature (T 300 K) and low...
A new ultrahigh vacuum (uhv) scanning funneling microscope (STM) with exchangeable samples and tips is constructed which is compatible with typical surface science techniques. The STM incorporates a number of novel features, including an optimized inner vibration isolation system. A tip-to-sample approach is performed by means of a simple, reliable all-mechanical system with only two parts moving...
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