Due to their outstanding mechanical properties diamond films are ideal candidates for many cutting and machining applications. However, industrial applications of these films are limited due to poor adhesion. Two main reasons causing this poor adhesion, which are based on the extrinsic physical and chemical properties of diamond, can be identified: High mechanical stresses induced by a difference of the thermal expansion coefficient between the diamond film and the substrate as well as a catalytic effect in case of metallic substrates containing iron-, cobalt- and nickel that, in combination with a methane atmosphere during deposition, leads to soot formation. One option to overcome these difficulties is to provide an interfacial layer that acts as adhesion layer as well as barrier layer to prevent the catalytic effect of the substrate elements. Even though some successful examples exist, this approach usually requires a time consuming and expensive multi-step process.

In this paper, the synthesis of nanocrystalline diamond/carbide composite films with a compositional gradient will be reported. Focusing on the example of diamond/ß-SiC the possibility to create a gradient layer ranging from ß-SiC to diamond in a controlled manner will be shown. The films are prepared by a Microwave Assisted Plasma Chemical Vapour Deposition process (MWCVD) using H2, CH4 and Tetramethylsilane (TMS) as reactive gases. The structure, grain sizes, and volume fractions of the components of these composite films, which consist of a mixture of diamond and carbide phase, can be controlled by adjusting the concentrations of the reactive gases in the gas mixture. This strategy, which handles all depositions in one process step, should allow for an improved diamond film adhesion on tools. The preparation and characterization of the composite films with special emphasize on their mechanical and tribological properties will be discussed and a short outlook on other diamond/carbide systems will be given.

The LiGA (Lithographie, Galvanoformung, Abformung) technique is a leading micromanufacturing process for making polymer- and metal- based high-aspect-ratio microscale structures. Molding replication is the key LiGA step for economical mass production of metal-based HARMS. Using a hybrid technique, we have fabricated microscale Ta mold inserts. Surface engineering of Ta inserts by electrochemical polishing followed by conformal coating deposition has enabled successful high-temperature micromolding of Al and Cu. In this paper, the molding performance of Ta inserts coated with amorphous hydrogenated carbon based coatings and amorphous silicon nitride based coatings is compared. Issues of maximum molding force, demolding force, and coating durability are addressed.

The thermodynamic stability of diamond (100) surfaces as a function of degree of hydrogen and oxygen-related termination coverage has been theoretically studied using DFT techniques. The results show that an exchange of the hydrogen atoms with hydroxyl groups is disfavored, whereas a corresponding exchange with oxygen atoms (in the ketone or ether position) is energetically preferred. The adsorption of up to about 50 % oxygen coverage (ether position) is, however, largely disfavored compared to a fully hydrogen-terminated surface. However, this oxygen termination will be energetically improved as the coverage increases above the 50 % level. The adsorption energy per terminating species (at 100% surface coverage) is −4.13 eV, −4.30 eV, −5.95 eV and 6.21 eV for H, OH, O(ketone) and O(ether) species, respectively.

Products derived from ethylene have and will continue to replace metallic materials traditionally used for transportation, building materials, and products we use in our everyday lives. As the demand continues to increase, a more suitable material for the outlet coils of ethylene pyrolysis heaters will have to be identified. In this study, we discuss utilization of scaled up pulsed deposition technology to deposit adherent carburization resistant coatings on the inner diameter of ethylene pyrolysis tubing with the intent of extending tube life. Ablation target material selection was based primarily on elevated temperature properties and the ability of the coating to prevent transformation of the inherent protective chromium oxide surface film to metal carbides while in service. The near optimal settings of the processing parameters for pulsed laser deposition of ceramic SiC on heat resistant tubing traditionally used for ethylene service were investigated using a semi quantitative controlled random search methodology. Minimization of the objective function which was based on width, thickness and coverage of the thin film resulted in an optimal deposition time of 4.3 minutes and surface finish of 272 nm.

The photochemical reaction processes, i.e., photo-dissociation of a reaction solution, defluorination of fluorocarbon [FEP], and substitution of a hydrophilic group, were measured in real time, when irradiating a Xe2 excimer lamplight on the water or ammonia solution as a reaction solution and FEP placed on the attenuated total reflectance [ATR] prism. In case of ammonia solution, with the increase in irradiation time, the absorption peaks of 3300 cm−1 and 1650 cm−1 gradually decreased, and the new absorption of -CF2-NH2 gradually appeared at 1410 cm−1, which presented the strongest absorption after UV irradiation for 25 minutes. The results indicate that the ammonia water has turned to amino groups. In addition, the contact angle of water was measured. When compared to the untreated sample, whose contact angle was 110 degrees, the contact angle of the sample treated with water became 31 degrees after the Xe2 lamp irradiation for 25 minutes, and that of the sample modified by ammonia water further improved to 27 degrees after the irradiation for 25 minutes.

The reactive ion etching of a range of hard coatings (TiN, TiCN, CrN and TiAlN) has been examined as a function of rf power, flow rate and pressure. The films were deposited by filtered arc deposition (TiN, TiAlN and CrN) or low energy electron beam (TiCN) on polished disc substrates of M2 tool steel. The flat surfaces were lithographically patterned with a grating structure (∼1 μm pitch). The TiN and TiCN layers have shown significantly higher etch rates (100-250 nm/min) than the CrN and TiAlN (∼5 nm/min) coatings. These regimes of higher and low etch rate were identified as ion-enhanced chemical etching and physical sputtering, respectively. In CF4/O2 plasma, the etch rate of the TiN and TiCN layers increased with rf power, flow rate and pressure which were parameters known to enhance the density of active fluorine species. The etch rates of TiN and TiCN layers were higher in CF4/O2 plasma than in CHF3/O2 gases in which polymer deposition was produced at pressure ≥ 35 mTorr.

In this paper, a low-temperature surface micromachining module with two sacrificial layers of polyimide is developed for the manufacturing of double-cantilever microbolometer focal plane arrays. The use of spin-on polyimide allows an all-dry final release step overcoming stiction problems often encountered in wet sacrificial etching processes. For the patterning of the polyimide, a plasma-enhanced chemical vapor deposited silicon oxide is employed as a mask layer. Anisotropic etching of both the mask film and the polyimide layer is accomplished by reactive ion etching. After patterning structural layers, sacrificial etching of the polyimide is conducted using an isotropic dry etch process in high-density oxygen plasma.

A novel surface engineering of nano-shaped materials, i.e., surface coating in supercritical fluid is proposed. Conformal deposition of a silicon-oxide thin film in supercritical carbon dioxide (scCO2) where O2 gas is miscible as an oxidizing agent is demonstrated. A uniform silicon-oxide film has been deposited even on backside of a nano-shaped SiO2, which is hard in the standard chemical vapor deposition. Filling of a Si-oxide into the horizontal gap has also been successfully achieved. Deposition of a fluorocarbon in scCO2 were tried to investigate surface modification using scCO2 and a hydrophilic SiO2 surface became water-repellent after the surface modification. These results indicate that the developed surface engineering in the supercritical fluid is promising technology in nanoscale device fabrication and micro (nano-) electromechanical systems.

Six nanocomposite coatings of yttria-stabilized zirconia (YSZ), Au, diamond like carbon and MoS2 have been studied by in situ tribometry. The coatings all had a nominal MoS2 content of between 14 and 18 mol%, while the concentrations of the other components were varied. Steady state friction coefficients in both dry (0.04–0.05) and wet sliding conditions (0.06–0.08) were similar for all coatings. However, by in situ tribometry, wear mechanisms were found to differ depending on coating composition and test environment humidity. Friction spiking in high YSZ coatings was identified with local plowing and scoring of the track followed by an extrusion of transfer film material. Trends in coating hardness and modulus are correlated to composition and coating wear processes.

In this study, we report an interesting phenomenon of “melt fracture” which was observed when a high viscosity film dewets from a film of lower viscosity. We propose that this phenomena is similar to the “melt fracture” or “shark skin” that is observed when extruding bulk polymer. We hypothesized that the “melt fracture” occurs as a result of shear which is imposed by the dewetting layer on the visco-elastic lower layer. The dewetting layer is adhered to the lower layer via entanglements across the polymer/polymer interface. When the other interface of the liquid film is adsorbed to an attractive substrate interface, a velocity gradient occurs in the film and therefore can result in the shear gradient. We proposed that if this shear rate exceeds the natural reptation time, melt fracture of thin film resulted. Screening the substrate interaction by first deposition a very thin layer of immiscible polymer such as poly (vinyl-pyridine) PVP reduced the degree of melt fracture. A DI 3000 Atomic Force Microscopy (AFM) was used to quantify the depth and the dynamics of the melt facture process.

The PTFE was modified into hydrophilic with 1/100 of the shots number required to obtain the same contact angle with water by the laser irradiation alone, when irradiating an ArF excimer laser on the sample surface at the moment of applying a 6 kV to the water placed on the PTFE surface to decrease the contact angle with water.

A plasma treatment method is widely used for plastic surface modification, but the hydrophilic property generated by this method fades away soon. On the other hand, we have previously reported that the ArF excimer laser light was applied on a sample surface in the presence of water to substitute hydrophilic groups, which was modified to have a long–lasting hydrophilic property. This method, however, needed 3000 to 10000 shots of the laser irradiation, and it is less economical compared with the plasma processing that requires only one–minute irradiation. There is an electro–wetting method, in which the contact angle with water decreases temporarily when a high voltage is applied between the water and the sample, but the contact angle is restored to its original position when stopping the voltage application.

Thus, we demonstrated the surface modification of PTFE maintaining the hydrophilic property for a long period with only 100 shots, by irradiating the ArF excimer laser on the sample at the moment when the wettability became high by the electro–wetting method. Water was placed in the gap between the silica glass and the PTFE to create a thin liquid layer with capillary phenomenon. A high voltage (6 kV) of direct current (DC) or alternating current (AC) was applied on the gap, and the ArF excimer laser was vertically irradiated on the sample surface. The water was photo–dissociated to produce H and OH. At the same time, the C—F bond of the PTFE was also photo–dissociated, and the F atom bonded to the H atom to produce HF. The OH group united with the dangling bond of C, which resulted in modifying the PTFE surface to be hydrophilic.

To evaluate the wettability of the modified sample, the contact angle with water was measured. Improving the contact angle with water from 110 degrees for the untreated sample to 50 degrees for the treated sample had needed 10000 shots at the laser fluence of 5 mJ/cm2. By combined high voltage application and ArF excimer laser irradiation treatments, however, the 50–degree contact angle was yielded with 500 shots, 1/20 of 10000, when applying the DC of 6 kV, and with 100 shots only, 1/100 of 10000, when applying the AC of 6 kV. Moreover, the modified sample was observed for a change in contact angle with passage of time. The contact angle was 60 degrees after applying the high voltage, and 110 degrees when stopped. On the other hand, the sample modified by combined the high voltage application and ArF excimer laser irradiation maintained the 50–degree contact angle for one month after stopping the voltage application.

A low refractive index, hard SiO2 film was photochemically coated on the surface of slab laser head at room temperature by using silicone oil and a Xe2 excimer lamp. Nd+:glass slab laser produces high power laser because the light is amplified with a repeated total reflection in the laser medium. However, an evanescent wave arises on the total reflection interface, which causes a loss of the light energy. A low refractive index film 2 μm thick is, therefore, needed to prevent this problem. The vacuum vapor deposition method as a dry process and the spin-coating method as a wet process are generally used for making optical thin films. The former method can laminate a hard thin film, but requires temperatures above 500°C, and the thermal denaturation of the optical substrate is unavoidable. On the other hand, the latter method can form a low refractive index thin film, but the produced thin film has a poor adhesiveness and a low hardness. Besides, all these films are inferior in water resistance. We, therefore, formed a water-resistant, hard, and low refractive index protective coating directly on the laser glass surface at room temperature with photochemical reaction by the Xe2 excimer lamp.

This paper reports our recent work on the improved mechanical properties of alumina thin films with embedded Fe and Ni nanoparticle layers. The Fe/Ni nanoparticles-alumina composite thin films have been deposited using a multi-target pulsed laser ablation technique. Every film consists of 10 layers of alumina and 9 intermediate layers of Fe or Ni nanoparticles. Alumina layer thickness kept constant (∼22 nm) and total thickness of multilayered films was in range 220-280 nm depending on metal deposition time. Composite thin films were deposited at six different substrate temperatures in the range 200-800°C. The mechanical properties measurements, performed by nanoindentation in continuous stiffness mode and applying Nix-Bhattacharya (hardness H) and King's model (Young's modulus E) for film-only properties, have shown that pure alumina films deposited at temperatures 200-500°C are relatively soft (H = 15 GPa, E = 190 GPa), while films deposited at ≥600°C are significantly harder (H = 32 GPa, E = 320 GPa). Grazing incidence XRD (GIXRD) data indicated that γ-alumina peaks exist in high temperature samples while alumina films deposited at ≥500°C were amorphous. Embedding Ni and Fe nanoparticle layers at 500°C led to significant increase of H and E (31 GPa and 365 GPa with Fe and 33 GPa and 380 GPa with Ni) and appearance of γ-alumina peaks in GIXRD. Embedding on metal nanoparticle layers does not change mechanical properties of alumina films deposited at 200°C, and significant hardening of metal containing films starts at 400°C. These results suggest that metal nanoparticles have a catalytic effect on the growth of alumina thin films with enhanced crystallinty. The effect of Ni and Fe nanoparticle size on mechanical properties of thin films has been studied times at substrate temperature 500°C using eight different metal deposition. HRTEM data have shown that metal nanopartiles have uniform particle size distribution and inter-particle separation in the layer. Size of Ni and Fe nanoparticles with highest effect on mechanical properties was 4 -6 nm.

A continuum (Mullins-type) model is proposed for the non-isothermal, isotropic evolution of a crystal surface on which mass transport occurs by surface diffusion. The departure from constant temperature is assumed induced by low-energy incident pulsed radiation. It has been previously shown experimentally and theoretically that such heating mode gives rise to the quasistationary regime, in which the surface temperature of a thick solid film oscillates about the mean value with the pulse repetition frequency. The implications of oscillatory driving with high frequency values on relaxation of surface ripple are examined; in particular, the traveling wave solutions with decreasing amplitude are detected numerically. Pulsed heating also results in faster smoothing of the ripple, compared to the case when the surface is at constant temperature which is same as the mean temperature in the pulsed heating mode. Impact on ripple shape is minor for ripple amplitudes considered.

A great deal of work has been carried out in recent years on temperature rise at the contact between sliding bodies with engineering scale roughness. However, as surfaces become smoother and loading decreases, in applications such as MEMS and NEMS devices, the analysis of surface temperature rise must consider the small-scale asperity height distributions and the surface forces that may be operating at small separations. The paper attempts to predict surface temperature rise at sliding contacts with small-scale roughness considering the influence of relevant parameters. The important observation here is that in addition to the dependence on load, speed and material parameters the contact temperature steadily increases with surface adhesion.

Micro-Raman spectroscopy is a valuable tool for thermometry of operational polysilicon MEMS devices. By using the temperature-calibrated response of the optical phonon peak of the polysilicon Raman signature and the micron-scale spatial resolution achieved with a 488 nm Ar+ laser Raman probe, we have obtained spatially resolved steady-state thermal profiles of Joule-heated thermal flexure actuators. The measured thermal profiles are further compared to one-dimensional numerical models of the thermal response of the electrically heated devices.

The physical properties of architectural sputtered coatings are considered in the context of their design, manufacture, transport and processing. The design constraints of high optical and thermal performance lead to the use of thin metal layers in interference coating stacks. This, in turn, determines the chemical and mechanical property challenges. In-service examples of film failure are presented along with practical countermeasures. Laboratory methods for ranking development coating systems are also discussed.

A thin polymer film subjected to an electrostatic field may lose stability at the polymer-air interface, leading to uniform self-organized pillars emerging out of the film surface. This paper presents a three dimensional dynamic model to account for the behavior. The coupled diffusion, viscous flow, and dielectric effect are incorporated into a phase field framework. Numerical simulations reveal rich dynamics of the pattern formation process and the substrate effect. The pillar size is insensitive to the film thickness, but the distance between pillars and the growth rate are significantly affected. The study suggests an approach to control structural formation in thin films with a designed electric field.

This study was undertaken to improve the bonding of fluorinated and non-fluorinated polymers to acrylic and silicone based adhesives. The polymeric materials were exposed to plasma which is comprised of methane and a second gas selected from air, Oxygen and Nitrogen or a mixture thereof. By application of surface analysis (XPS), the optimized functionality can be incorporated in the surface of desired polymers to enhance the bond ability of prepared films for pressure sensitive tape applications. Perfluoroalkoxy-tetrafluoroethylene copolymer PFA, fluorinated ethylene-propylene FEP, Polytetrafluoroethylene PTFE, and Polyester materials were exposed to this plasma. The treated samples were coated with adhesives and the adhesion to steel, holding power and other properties associated with tapes performance were studied.

Organic silicone oil was photo–chemically oxidized to change into SiO2 by using a ultraviolet (UV) excimer lamp, which developed an over–coating for a nonlinear optical crystal.

In general, nonlinear optical crystals are used as a wavelength conversion element for laser. The crystals are, however, deliquescent and absorb moisture in the air, which causes clouding. They need heating in the oven to prevent it. It is desired to develop a protective film on the nonlinear optical crystals so as to be waterproof and transmit UV rays. We have, then, developed the waterproof and protective film on a KH2PO4 (KDP) surface, which was photo–chemically oxidized by using a silicone oil and Xe2 excimer lamp. The silicone oil was spin–coated on the KDP crystal surface, and then the Xe2 excimer lamp was vertically irradiated to the crystal surface. The O atoms in the air were photo–excited with the UV photon to generate high active O atoms. At the same time, the C—H and the Si—C bonds of the silicone oil were photo–dissociated because the photon energy of the UV photon is higher than the bonding energies of the C—H and Si—C. The siloxane of the silicone oil was consequently linked with the O2 that had been absorbed on the crystal surface to form SiOn. As a result, the SiO2 film was formed on the KDP crystal surface by the photo–oxidation of silicone oil.

The infrared spectroscopy analysis (ATR-FTIR) was carried out to investigate the modified film. The results showed that as the time of lamp irradiation extended, the absorption peak of the —CH3 groups at 2900 cm−1 decreased, but the absorption peak of the —SiO groups at 1050cm−1 increased. At the lamp irradiation time of 90 minutes, the UV transmittance of the treated silicone oil improved to 88.9 % at the 260 nm, which is the wavelength of the fourth harmonic generation, while that of the untreated silicone oil was 56 %.

The treated and untreated KDP crystals were tested for their waterproofing. The untreated crystal was completely dissolved thirty minutes after soaking in the water, and on the contrary, the KDP crystal with the film coating has neither been dissolved nor gotten cloudy for three months when soaking in water.