Metal films structure

Wet chemical etching is also a commonly used process to pattern the metallic film structure. In these cases, a suitable solvent for the metallic film is used to dissolve or etch away the exposed area of the metallic film. This wet etching technique has been used for various metallic films, such as gold, copper, aluminum, and others. However, there are cases where chemical etching of the metal can be difficult. For instance, the etching of the platinum film is not easy because of the required etchant for the platinum film. One of the patterning processes to overcome the potential... 

Avadyne. [inerce Stevens] Water or ah ol dilutable two-part uretiiane prepolymer emulsion adhesive for lantination of film-to-film and filriirto-metallized film structures. 

Avadyne. [Herce Stevens] Water urethane prepolymer emulsion adhesive for laniination of film-to-film and film-to-metallized film structures. 

Madey T E, Guan J, Nien C-H, Dong C-Z, Tao H-S and Campbell R A 1996 Faceting induced by ultrathin metal films on W(111) and Mo(111) structure, reactivity, and electronic properties Surf. Rev. Lett. 3 1315... 

It is known that thin (-20 A) passive films form on iron, nickel, chromium, and other metals. In s ressive environments, these films provide excellent corrosion protection to the underlying metal. The structure and composition of passive films on iron have been investigated through iron K-edge EXAFS obtained under a variety of conditions, yet there is still some controversy about the exact nature of... 

In summary, the forte of SNMS is the measurement of accurate compositional depth profiles with high depth resolution through chemically complex thin-film structures. Current examples of systems amenable to SNMS are complex III-IV laser diode structures, semiconductor device metallizations, and magnetic read-write devices, as well as storage media. 

If a sample of polycrystalline material is rotated during the sputtering process, the individual grains will be sputtered from multiple directions and nonuniform removal of material can be prevented. This technique has been successfully used in AES analysis to characterize several materials, including metal films. Figure 9 indicates the improvement in depth resolution obtained in an AES profile of five cycles of nickel and chromium layers on silicon. Each layer is about 50 nm thick, except for a thinner nickel layer at the surface, and the total structure thickness is about 0.5 pm. There can be a problem if the surface is rough and the analysis area is small (less than 0.1-pm diameter), as is typical for AES. In this case the area of interest can rotate on and off of a specific feature and the profile will be jagged. 

Table 1 contains the metal-to-metal engineering property requirements for Boeing Material Specification (BMS) 5-101, a structural film adhesive for metal to metal and honeycomb sandwich use in areas with normal temperature exposure. The requirements are dominated by shear strength tests. Shear strength is the most critical engineering property for structural adhesives, at least for the simplistic joint analysis that is commonly used for metal-to-metal secondary structure on commercial aircraft. Adhesive Joints are purposefully loaded primarily in shear as opposed to tension or peel modes as adhesives are typically stronger in shear than in Mode I (load normal to the plane of the bond) loading. 

The significance of corrosion protection has risen sharply in recent years for a number of reasons (1) because of efforts to reduce the metal content of parts (e.g., by using thinner metallic support structures) (2) with the use of new types of equipment and processes involving expensive equipment operated under extreme conditions, such as nuclear reactors and jet and rocket engines and (3) in connection with the development of products having extremely thin metal films, such as printed circuit boards and integrated circuits. 

Self-assembled monolayers (SAMs) [8] The layers are formed by heterologous interaction between reactive groups, such as thiols, and noble metals, such as gold or silver. Since the molecules are selectively adsorbed on these metals, film growth stops after the first monolayer is completed. The molecular aggregation is enthalpy driven, and the final structure is in thermodynamic equilibrium. 

We and others have been involved in the study of such systems including Cu/Au(lll),85 86 Ag/Au(lll),87 Pb/Ag(lll),88 and Cu/Pt(lll).89 The first three systems involved the use of epitaxially deposited metal films on mica as electrodes.90 92 Such deposition gives rise to electrodes with well-defined single-crystalline structures. In the last case a bulk platinum single crystal was employed. Because of the single-crystalline nature of the electrodes, polarization dependence studies could be used to ascertain surface structure. 

For the present purpose, we take the term ultrathin to refer to an evaporated metal film where the concentration of metal on the substrate is low enough for the film to consist of small isolated metal crystals. If the average concentration of metal atoms on the substrate is of the order of a monolayer or less, the metal crystals are small enough for ultrathin films to serve as models for highly dispersed metal catalysts, but where surface cleanliness and catalyst structure can be better controlled. 

The type of intermediate shown in structure (B) has also been supported by Muller and Gault (119) who showed that in the reaction of 1,1-dimethylcyclopropane with deuterium over a series of thick evaporated metal film catalysts, it was only on platinum that 1,1,3-da-neopen-tane (and 1,1,3,3-d4-neopentane) were dominant products. On palladium, iron, rhodium, nickel, and cobalt the major product was 1,3-d2-neopentane. 

OLED on an Al-PET substrate. The device performance does not deteriorate after repeated bending, suggesting that there is no significant stress-induced change in the characteristics of the OLEDs fabricated on PET foil [71,82]. The results demonstrate the feasibility of fabricating flexible displays using a variety of plastic substrates including metal-laminated plastic foils, or a metal film sandwiched between two plastic foils. The flexible device structures enable a display to conform, bend, or roll into any shape and thus make possible other product concepts. 

The general theory of 4.3 can now be applied, with some modification, due to the fact that the substrate electronic structure consists of discrete states arising from the metal film, in addition to the delocalized band states of the semiconductor. The adatom GF (5.56) can be written as (cf. (4.70))... 

X-ray diffraction—Measurement of atomic and ionic spacings in crystal structures and thicknesses of thin metal films. 

In this chapter, we shall use DFT to investigate the extent to which the oxide support alters the electronic structure of the deposited metal as a result of charge transfer at the metal-oxide interface. We will use CO chemisorption as a function of Pt film thickness to demonstrate how changes in the metal electronic structure can lead to chemisorption trends that deviate from expectations based on the current theory of molecular adsorption. 

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