Aluminum deposition techniques

Janicke et al. [63] applied a sol-gel-type deposition technique by filling micro channels with aluminum hydroxide solution, which was dried and caldned at 550 °C thereafter. Platinum was introduced as catalyst by impregnation on the coating up to three times, resulting in different loadings of the precious metal. 

Outside of these seemingly niche markets the main driving force for using non-aqueous electrolytes has been the desire to deposit refractory metals such as Ti, Al and W. These metals have numerous applications, especially in the aerospace industry, and at present they are deposited primarily by PVD and CVD techniques. The difficulty with using these metals is the affinity of the metals to form oxides. All of the metal chlorides hydrolyze rapidly with traces of moisture to yield HC1 gas and hence any potential process will have to be carried out in strict anhydrous conditions. Therefore the factor most seriously limiting the commercialization of aluminum deposition is the engineering of a practical plating cell. 

The Principles and Techniques of Electrolytic Aluminum Deposition and Dissolution in Organoaluminum Electrolytes... 

Processing Techniques for Electrolytic Aluminum Deposition from Electrolytes Containing Aluminum Alkyls. 211... 

Fig. 1 shows one of the first electrolytically deposited alumimun coatings to be obtained from this type of electrolyte. Since electrolytic aluminum deposition from this system has no true smoothening effect, thick layers become even rougher, as illustrated by the thickly coated cathode plate shown in Fig. 1. The cathodic deposition and the anodic dissolution of aluminum corresponded to almost 100 <7o of the amount expected according to the Faraday rule, which is an important prerequisite for even considering using this electrolysis technique for technical applications. Independently of the layer thickness, the deposited aluminum layers are found to be ectraordinarily pure. Spectroscopic investigations have revealed purities of up to 99.999%. Even when relatively impure raw aluminum with purities of 99.7% functions as the anode, very pure aluminum can be deposited. Therefore, obviously not only a technique of electroplating aluminum was discovered, but also a method of...

Available forms Structural shapes of all types, plates, rods, wire foil flakes, powder (technical and USP). Aluminum can be electrolytically coated and dyed by the anodizing process (see anodic coating) it can be foamed by incorporating zirconium hydride in molten aluminum, and it is often alloyed with other metals or mechanically combined (fused or bonded) with boron and sapphire fibers or whiskers. Strengths up to 55,000 psi at 500C have been obtained in such composites. A vapor-deposition technique is used to form a tightly adherent coating from 0.2 to 1 mil thick on titanium and steel. 

At present it is felt that in this context, a fundamentally important recent advance in the silicon-based semiconductor industry is the development of copper interconnects on chips. Tliis new technology replaces aluminum or aluminum alloy (e.g., Al-Cu) conductors produced via vacuum-based deposition techniques with copper conductors themselves produced through electroless and/or electrodeposition. Specifically, vacuum-based deposition techniques include physical vapor deposition (PVD) and chemical vapor deposition (CVD). 

The phosphorescent organic light emitting diodes (PHOLEDs) based on Ir(dmp>py)3 complexes were fabricated by the vacuum deposition technique with the following configuration ITO/copper phthalocyanine (CuPc, 10 nm) as hole injection layer/4,4 -bis[(l-naphthyl)(phenyl)-amino]-l,l -biphenyl (NPD, 40 nm) as hole transport layer/CBP Ir(dmppy)3 (8%) (20 nm) as emissive layer/2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline (BCP, 10 nm) as a hole blocking layer/ tris-(8-hydroxyquinoline)aluminum (Alqs, 40 nm) as an electron transport layer/LiF (1 nm) as electron injection layer/ A1 (100... 

A similar use of the technique of vacuum evaporation, is put to work in the manufacture of aluminized TV picture tubes. In this case, the picture tube is used as the vacuum chamber and aluminum is flashed from a heated tungsten filament projecting into the neck of the tube. The aluminum deposits on the inside surface of the tube and covers the phosphor screen. When in use, the aluminum film serves to reflect the light emitted from the phosphor screen which would otherwise be lost inside the tube. In this respect, the aluminum film fulfills the same function as the mirror in back of a kerosene lamp. 

Several techniques have been developed to deposit alumina films on different surfaces such as those of semiconductors or metals. These films find apphcation in various areas. In most cases, amorphous alumina films are desired. Depending on the deposition techniques, various precursors may be used the following combinations have been reported plasma-enhanced atomic layer deposition using trimethylaluminum (112), metal-organic chemical vapor deposition using aluminum tri-iso-propoxide (113), and condensation from the gas phase using laser-evaporated alumina (114). Similar evaporation techniques can also be apphed to prepare Y-AI2O3 powders (115,116). 

As stated above, a variety of deposition techniques have been developed in recent years to produce amorphous alumina coatings (112—115), among them the anodization of aluminum. Amorphous aluminas, denoted as a-Al203 or sometimes as P-AI2O3, can also be prepared by conventional liquid-phase reactions (134), by the decomposition of some hydroxides, or by sol-gel procedures aimed at the preparation of mesoporous materials. In several instances, IR (110) and Raman (135) spectra have demonstrated that amorphous aluminas may contain impurities originating from the... 

Polymer surfaces are modified by plasma techniques for interfacial enhancement [4-10], Au, Ag, Pd, Cu and Ni were coated on poly (methylmethacrylate) (PMMA) by barrel technique [11]. Coating of A1 alloys on PET was compared with Ti layer under A1 alloys [12]. Thin Aluminum oxide coatings have been deposited on various uncoated papers, polymer-coated papers and plain polymer films using atomic layer deposition technique [13]. The isotactic polypropylene (iPP) and A1 composite is widely used as television cable electromagnetic shielding materials [14], The reflection of infrared light depends on geometry of the surface of alumi-... 

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