Reactive Low Voltage Ion Plating Research Articles

Critical field patterns in optical Fibonacci multilayers

Optical coatings with 13, 34, 55, and 89 quarter-wave layers of high- and low-index dielectric materials arranged in Fibonacci sequences F6, F8, F9, and F10, respectively, were deposited with use of a reactive low-voltage ion plating process. The calculated average transmission (Tave) for ϕ = (1/2 ± 1/4)π follows a power law Tave ≈ Nm−δ, where Nm is the number of optical quarter-wave layers in a Fibonacci sequence Fm. The critical exponent δ for these multilayers is compared with a renormalization calculation of the exponent governing the total energy width for an electronic system of Fibonacci layers. Spectral-transmittance measurements of the experimental Fibonacci multilayers show some deviation from the calculated spectral transmittance, which is due primarily to absorption in the short-wavelength range, but these measurements do still indicate that the observed optical field patterns are critical.

Metal-oxide thin films with reduced residual absorption deposited in a reactive low-voltage ion-plating process with N2 activation

Mechanisms have been investigated for increasing the abundance of atomic oxygen in the process environment during reactive low-voltage ion plating, a plasma-assisted evaporation process. Feeding several percent of nitrogen into the coating chamber led to enhanced oxidation and consequential reduction of residual optical absorption of ion-plated oxide films of tantala.

Corrosion-resistant front surface aluminum mirror coatings

Front surface metal mirrors need protection of the inherently fragile metal film deposited on a glass substrate. Conventional evaporated dielectric thin-film overcoats provide limited protection because of their less than dense packing. These films usually have a columnar structure with voids between the columns. The voids give access to the underlying metal film for humidity and corrosive gases or liquids. Some progress in developing better coatings was made in the early 1980s with ion-assisted deposition. Front surface aluminum mirrors with dielectric thin films deposited by reactive low-voltage ion plating have a still higher survival time, by a factor of up to 3 under comparable test conditions. The transmission of our best samples increased to only 10% when immersed in 0.2 M NaOH for 20 h. By comparison, an unprotected aluminum film dissolves in less than 5 mm. Electron beam evaporated dielectric coatings provide protection for about 1 .5 to 2 h in the same test solution. The reason for the significant improvement brought about by reactive low-voltage ion plating deposition, and its advantage for large-scale production is discussed.

Ion plating as an industrial manufacturing method

Plasma-supported reactive deposition technologies set up possibilities to produce high-quality compound films for various applications. In the Balzers activated reactive ion plating (ARIP) system the hot filament cathode of a non-self-sustaining arc source provides electrons directed to an anodic crucible to evaporate Ti. On their way, the low-voltage electrons produce a magnetically confined discharge plasma in the working and reactive gas and in the coating material vapor. Ionization, dissociation, and excitations occur. By acceleration to negatively biased, precleaned substrates, the kinetic and potential energy of the positive ions and excited species is responsible for the formation of well adherent, hard, dense, and stoichiometric compound films such as TiN and TiCxNy. ARIP is used worldwide in an economic high-volume production of wear-resistant coatings on steel tools and machine parts. Another commercial system was obtained by combining a 270° e-beam evaporator with the thermionic arc source. Using self-biasing of insulators, unheated glass substrates can be coated by this reactive low-voltage ion plating process with hard, dense, generally amorphous oxide and nitride films for particularly optical applications. Multilayers with stable optical characteristics have been obtained showing excellent mechanical and environmental resistivity.

Integrated optical sensors based on reactive low-voltage ion-plated films

Abstract Thin films fabricated by reactive low-voltage ion plating can be used to manufacture stable and sensitive integrated optical sensors. As an application, an optical humidity sensor with a high sensitivity for gases with low humidities is demonstrated.

Properties of ion-plated Nb2O5 films

Single films of Nb2O5 have been deposited on various substrates by reactive low voltage ion plating in a Balzers BAP 800 ion plating system. Chemical composition, structure, and optical and mechanical properties have been investigated. Nb2O5 offers promise as a high index optical film material in the wavelength range from 380 nm to 9 μm.

Characterization of Ta2O5 layers by electron spectroscopy for chemical analysis rutherford backscattering spectrometry, nuclear reaction analysis and optical methods

Ta2O5 layers were deposited by reactive evaporation (RE) and reactive low-voltage ion plating (IP). The layers were characterized by thin film analysis and optical methods. The deposition techniques have a strong influence on the film density, the refractive index and on the hydrogen content, which was determined by the 15N technique. Differences in the stoichiometry are observed which can be correlated with the deposition conditions.

All-oxide broadband antireflection coatings by reactive ion plating deposition

Coating experiments were made with reactive low-voltage ion plating to achieve the computer designed performance of all-oxide broadband antireflection systems on BK-7 glass. Reasonable accordance between calculated design and coating experiment as well as reliable production have been demonstrated.