G. A. Al-Jumaily

Properties of TiO2 and SiO2 thin films deposited using ion assisted deposition

TiO2 and SiO2 films deposited using ion assisted deposition are investigated as a function of ion energy and current density. Optical constants, possible ion source contaminants, and optical scatter are examined for samples deposited at ambient (∼75°C) and elevated (∼250°C) substrate temperatures.

Microstructure characterization by angle-resolved scatter and comparison to measurements made by other techniques

The theory and measurement of angle-resolved scatter are described. Values of rms roughness that were obtained by using this technique to characterize four different materials are compared with values that were obtained by using a total integrated scatter measuring instrument, an optical profiler, and a mechanical profiler. The spatial frequency bandwidths and modulation transfer functions of the four instruments are different, and results are described in light of these differences.

Ion assisted deposition of optical and protective coatings for heavy metal fluoride glass

Heavy metal fluoride glass materials are attractive for optical applications in the near UV through IR wavelength regions. However, many compositions are relatively soft and hygroscopic and possess low softening temperature (250–300°C). We have applied ion assisted deposition (IAD) techniques to deposit MgF2, SiO2, and A12O3/SiO2 thin filmstructures on fluorideglass substrates at ambient substrate temperature (~100°C). The coatings deposited using IAD improve the environmental durability of the fluoride glass and appear to have reasonably good optical characteristics; without application of IAD, the deposited coatingsare not durable and have poor adhesion.

Surface smoothing effects of thin film deposition

Deposition of 0.2–0.5-μm thick Cu thin films onto a polished Cu substrate causes a reduction of scatter due to high spatial frequency microroughness by as much as a factor of 10 and a reduction in total integrated scattering by as much as a factor of 4.

Optical properties of ThF 4 films deposited using ion-assisted deposition

The effects of ion-assisted deposition on the properties of thorium fluoride films deposited at ambient temperature are examined. (AIP)

Influence of metal films on the optical scatter and related microstructure of coated surfaces.

Deposition of 0.1–1.0-μm thick metal on a CaF2 coated Si wafer causes a reduction in optical scatter and related microroughness. This effect is not observed when the coated surfaces are examined using a surface profilometer (Talystep). Scanning electron micrographs indicate that coated surfaces are smoother than uncoated surfaces.

Frequency Response Characteristics Of A Mechanical Surface Profilometer

The frequency response characteristics of a mechanical surface profilometer were examined. The treatment was based on a computational model that tracks the motion of a spherical stylus as it traces a mathematically defined surface. The stylus was found to possess a nonlinear response to the surface profile. The effects of the nonlinearity on the frequency response and spatial frequency bandwidth of the stylus profilometer were examined. The model assumes that no external force acts on the stylus; therefore, effects such as surface deformation were not investigated.

Contamination analysis of TiO2 thin films deposited using ion assisted deposition

Abstract Elastic backscattering and recoil detection techniques have been used to analyze TiO2 films for possible contaminants introduced during O2+ ion assisted deposition. The principle impurities (H, C and W) together with the TiO2 film stoichiometry were monitored as a function of O2+ ion energy (60–500 eV), O2+ current density (0–180 μA cm 2 ) and the substrate temperature (50–250°C). The main findings were: (1) TiO2 film stoichiometry improved with increasing O2+ current except for the case of low temperature and high O2+ energy, (2) W levels were directly proportional to O2+ current, (3) C contamination increased at the higher temperatures and (4) the H levels were relatively insensitive to the deposition parameters. The last two findings indicate that the source of H and C contamination may have been residual gases in the vacuum chamber.

Ion Beam Assisted Deposition Of Optical Thin Films - Recent Results

We have examined the properties of dielectric (Ti02, Si02, -Al203, Ta205 and Hf02) films deposited using ion-assisted deposition (IAD). The films were characterized using an angularly resolved scatterometer, spectrophotometer and Raman spectroscopy. A reduction in optical scatter, especially that due to low spatial frequencies, is observed for films deposited with simultaneous ion bombardment. Higher values of refractive index are obtained for films deposited using IAD. Raman spectra indicate a crystalline phase change in TiO2 films is induced by bombardment of samples with 02 ions during deposition. Other experimental data and the effects of the induced phase transition on the optical properties of TiO2 will be discussed.

Comparison Of Optical Scatterometer And Profilometer Techniques For Characterizing Smooth Surfaces

Several techniques are available for characterizing the surface microstructure of smooth components. Often it is necessary to compare the results from two or more of these techniques. This can lead to problems unless it is understood that all measurement techniques are bandwidth limited, and each technique has a characteristic transfer function. We will discuss several techniques in this regard, including the optical profilometer (WYKO), the optical scatterometer (both angle-resolved and TIS), and the mechanical profilometer (Talystep). A number of samples having different microstructure properties were characterized using these techniques, and results will be discussed.