Thin Films Of Silicon Monoxide Research Articles

Growth direction of oblique angle electron beam deposited silicon monoxide thin films identified by optical second-harmonic generation

Oblique angle deposited (OAD) silicon monoxide (SiO) thin films forming tilted columnar structures have been characterized by second-harmonic generation. It was found that OAD SiO leads to a rotationally anisotropic second-harmonic response, depending on the optical angle of incidence. A model for the observed dependence of the second-harmonic signal on optical angle of incidence allows extraction of the growth direction of OAD films. The optically determined growth directions show convincing agreement with cross-sectional scanning electron microscopy images. In addition to a powerful characterization tool, these results demonstrate the possibilities for designing nonlinear optical devices through SiO OAD.

Thermally Evaporated SiO Thin Films As a Versatile Interlayer for Plasma-Based OLED Passivation

Silicon monoxide (SiO) thin films were introduced as an efficient interlayer for achieving plasma-based organic light-emitting diode (OLED) surface passivation. The SiO thin films could be consecutively formed via thermal evaporation, without breaking the vacuum, after deposition of the OLED cathode. The plasma resistivity and UV-blocking characteristics of the SiO interlayer protected the OLED devices against electrical and optical degradation during the plasma-enhanced atomic layer deposition (PEALD) and plasma-enhanced chemical vapor deposition (PECVD) passivation processes. In addition, the nonconformal deposition and hydroxyl group-rich surface characteristics of the SiO thin films yielded enhanced surface pinhole coverage and a higher initial film density in the subsequently deposited PEALD-based Al2O3 barrier film. As a result, the OLEDs with a SiO/Al2O3 bilayer passivation layer displayed a remarkably increased device shelf life compared to devices prepared using Al2O3-only passivation. A MOCON test showed that the water vapor transmission rate (WVTR) of the SiO/Al2O3 bilayer film was 0.0033 g/(m(2) day), 2.3 times lower than the rate of a single Al2O3 barrier film. The results of our study demonstrated the multipurpose role of a SiO interlayer in plasma-based OLED passivation. The layer acted as a damage-free protective layer for the underlying OLED devices and an assistant layer to improve the upper barrier film performance.

Effect of the Er-Si interatomic distance on the Er3+ luminescence in silicon-rich silicon oxide thin films

The photoluminescence (PL) intensity of Er-doped silicon monoxide thin films obtained by coevaporation of silicon monoxide and Er is studied for different deposition and annealing atmosphere compositions. All samples exhibit a luminescence peak at 1.54 μm assigned to the radiative deexcitation of Er3+. PL intensity is highest when nitrogen atoms are incorporated in the layer during deposition. Extended x-ray absorption fine structure spectroscopy evidences that the local order around the erbium ion is modified in the presence of nitrogen. In particular, the shorter the Er-Si interatomic distance is, the higher the Er3+ PL intensity is.

Optical and structural characterisation of single and multilayer germanium/silicon monoxide systems

Germanium and silicon monoxide thin films prepared with different evaporation conditions are analysed. Substrate temperatures from 30 to 370 °C and deposition rates from 0.3 to 3.0 nm/s for SiO and from 0.5 to 1.5 nm/s for Ge films are considered. Optical constants in the mid-infrared range are derived from transmission spectra and their variation with deposition conditions is related to structural and morphological changes in the films. Taking into account the results of the single layers study, deposition conditions adequate for both SiO and Ge thin films in multilayer optical coatings for the mid-infrared range of the spectrum are selected. The optical characterisation of a ten-layer bandpass filter, designed considering the experimental optical constants for both materials and prepared with the selected deposition conditions, is presented. The results indicate that the departure of experimental transmittance in the mid-infrared range from the design is mainly due to thickness deviations.

Improvement of the ITO-P Interface in a-Si:H Solar Cells Using a Thin SiO Intermediate Layer

AbstractThe use of ITO thin films on glass/ITO/p-i-n/metal amorphous silicon solar cells is reviewed. It is suggested a new application for silicon monoxide thin films on the ITO-p interface, as an intermediate layer, to minimize the ITO thin film deterioration process, during the early stage of exposure to a silane plasma rich in hydrogen. The thickness of the silicon monoxide thin films is chosen not to worsen the optical and electrical properties of the ITO thin films. The ITO-p interface is optimized (due to impurities diffusion decrease), leading to an overall improvement of the device performance

Improvement of the ITO-p Interface In a-SI:H Solar Cells Using a Thin SiO Intermediate Layer

AbstractThe use of ITO thin films on glass/ITO/p-i-n/metal amorphous silicon solar cells is reviewed. It is suggested a new application for silicon monoxide thin films on the ITO-p interface, as an intermediate layer, to minimize the fTO thin film deterioration process, during the early stage of exposure to a silane plasma rich in hydrogen. The thickness of the silicon monoxide thin films is chosen not to worsen the optical and electrical properties of the ITO thin films. The TO-p interface is optimized (due to impurities diffusion decrease), leading to an overall improvement of the device performance.

Refractive index of vacuum-evaporated SiO thin films: Dependence on substrate temperature

The substrate temperature dependence of the IR refractive index of vacuum-evaporated silicon monoxide thin films is reported. This process parameter can control the refractive index of the samples provided that the other parameters (pressure, deposition rate, source temperature etc.) are maintained under reasonably constant conditions during the evaporation process. Our results demonstrate the possibility of obtaining SiO thin films with different and controlled refractive indices by controlling the substrate temperature. Also, a process temperature has been obtained at which no dispersion of the refractive index in the IR 1–5 μm range occurs.

Two-dimensional array of diffractive microlenses fabricated by thin film deposition

A 2-D array of 10 x 10 diffractive lenslets was fabricated and tested. Each lenslet has a rectangular aperture and a size of 1.5 mm x 1.5 mm. The focal length of each lenslet is 47 mm. The array was produced by depositing thin films of silicon monoxide on a quartz glass substrate and by using photolithographic techniques. The performance of the lenslets is based on the diffraction of light at a Fresnel zone plate (FZP). The FZP pattern was implemented as a phase structure with eight discrete levels. The diffraction efficiency was measured to be 91%.

The structure-mechanical property relationship of amorphous silicon monoxide thin films

The structure-mechanical property relationship of amorphous silicon monoxide thin films

The structure-mechanical property relationship of amorphous silicon monoxide thin films

Amorphous silicon monoxide (SiO x ) thin films were produced by Joule heating and electron bombardment evaporative methods in high vacuum. Real-time force vs. elongation curves were recorded for SiO x films 200–300 nm thick on an instrument known as the nanotensilometer. The elastic modulus, fracture stress and plastic deformation were determined from hard mode tensile testing. The elastic modulus varied from 53 to 75 GPa independent of film preparation method. No plastic deformation was detected for successive tensile pulls on a given specimen. Estimates of plastic deformation never exceeded 0.015% strain at the point of fracture. Failure occurred by brittle fracture and fracture stress ranged from 70 to 380 MPa. The film composition determined by Rutherford scattering gave an x value in SiO x within the range 0.9–1.0 for all films independent of evaporation method. The structure of the SiO x was determined to be of an amorphous character by electron diffraction and structure imaging using transmission electron microscopy.

A Study of Electron Spin Resonance in Thin Films of Silicon Monoxide with Cerium Oxide

A Study of Electron Spin Resonance in Thin Films of Silicon Monoxide with Cerium Oxide

The Effect of Temperature on the Optical Absorption Edge of Amorphous Thin Films of Silicon Monoxide

AbstractThe analysis of the optical absorption edge as a function of temperature is discussed with particular reference to amorphous silicon monoxide films. The validity of the Urbach rule is investigated and the respective parameters are estimated. Experimental measurements on thin SiO films of the optical energy gap as the temperature is varied in the range 100 to 474 K, are reported and the results are discussed in terms of current theory.

The optical absorption edge of amorphous thin films of silicon monoxide

The absorption edges of vacuum-evaporated silicon monoxide films are studied and a general equation based on the absorption being due to non-direct electronic transitions in k-space is found to be compatible with the experimental results. The optical energy gap, E opt, is determined from the high absorption region of the fundamental edge. Measurements on films deposited at different rates and having different thicknesses are analysed and discussed in terms of the values of E opt. The form of the absorption edge remains similar for annealed films but annealing has the effect of increasing the values of E opt. The experimental results are related to earlier published work based on measurements of electron spin resonance and refractive index of films prepared under different conditions and additional experiments are reported.

The optical absorption edge of amorphous thin films of silicon monoxide and of silicon monoxide mixed with titanium monoxide

The optical absorption edge of amorphous thin films of silicon monoxide and of silicon monoxide mixed with titanium monoxide

Formation of SiH bonds when SiO is deposited on alumina

Thin films of silicon monoxide have been deposited on alumina surfaces and examined by inelastic electron tunneling spectroscopy. A strong absorption peak at 2210 cm−1 reveals the formation of SiH bonds in the presence of trace amounts of water. It is inferred that a reaction between SiO and –OH groups to yield SiH bonds is catalyzed by the alumina surface.

The growth of mouse neuroblastoma cells in controlled orientations on thin films of silicon monoxide

Mouse neuroblastoma cells have been grown in orientated arrays on fine lines of silicon monoxide evaporated onto plastic Petri dishes. The axon-like processes produced by these cells on attachment to this surface have also been found to grow along the silicon monoxide lines, giving chains of neuroblastoma cells connected by processes.

Low Temperature Migration of Gold Through Thin Films of Silicon Monoxide

A study of gold migration in silicon monoxide in the temperature range 200°–600°C has been carried out using the Rutherford scattering technique. It has been found that for plane sources, diffusion occurs which can be characterized by the normal Arrhenius form. For thick gold sources this temperature relation is followed until the silicon‐gold eutectic temperature is exceeded at which point a rapid migration of the gold occurs and a high concentration is established in the film.

Thermally stimulated currents in thin films of silicon monoxide doped with metallic impurities : J. Pinguet and S. S. Minn. Solid State Commun.15, 1277 (1974)

Thermally stimulated currents in thin films of silicon monoxide doped with metallic impurities : J. Pinguet and S. S. Minn. Solid State Commun.15, 1277 (1974)

Birefringence in silicon monoxide films used for aligning liquid crystal layers

Obliquely evaporated thin films of silicon monoxide are widely used to align nematic liquid crystal layers in electro-optic devices, but the mechanism of this alignment is incompletely understood. This letter reports that such films exhibit birefringence, despite the basically amorphous structure of SiO. The nature of the birefringence appears to be related to the manner in which the films align the nematic director. It is suggested that the phenomenon may be due to form birefringence caused by anisotropic morphology in the films.

Thermally stimulated currents in thin films of silicon monoxide doped with metallic impurities

We have determined the median values of the relaxation time and activation energy of thermally stimulated charges in silicon monoxide doped with metallic impurities. The results are compared with those obtained from alternating current experiments.