Vacuum deposition system

Fig. 1. Vacuum deposition system having a plasma processing capabiHty, where the dashed lines represent optional additions to a system.

The study of CD semiconductors, and in particular CdSe and CdS, for use as photoelectrodes in photoelectrochemical cells is connected with this use, although much farther from likely application. This study was driven, to a large extent, by the simplicity of deposition of the films, a particularly sought-after requirement for this purpose, both from the point of view of applications and because it allowed many groups (usually chemists) who maybe did not have ready access to conventional vacuum deposition systems to prepare the films. 

Aromatic hydrocarbon pentacene is important for application in OTFTs as it has superior field effect mobility, good semiconducting behavior, and stability [153], The chemical structure is shown in Fig. 6.10. Pentacene semiconductor films can be fabricated by sublimation in a vacuum deposition system. Optimization of the fabrication parameters, such as the substrate temperature and deposition rate, can yield a highly ordered pentacene film with improved device performance. Oriented films have optical and electrical anisotropies. 

Bulk wave devices are commonly used as deposited mass or film thickness monitors in vacuum deposition systems. Their use in this context has been described by Czanderna (5) and is the subject of a continuing series of monographs (39). Bulk wave mass detectors have also been applied to the detection and quantitation of aerosols and suspended particles. Surface deposition was achieved by the use of a surface adhesive (40), electrostatic precipitation (41), or inertial impact (42). The mass sensitivity of bulk wave devices appears more than adequate for these applications, and there are no reports in the literature of the development of simple SAW device mass sensors which potentially could yield higher mass sensitivities. 

Metallization occurs in high vacuum deposition systems using electron beam, flash, and resistive heating systems to evaporate the metal onto the substrate. Sputtering systems perform the same function under partial vacuum. Etching, either dry (plasma) or wet etching, processes remove... 

In manufacturing, it is important to keep equipment logs for the equipment and instrumentation being used. These logs contain information as to when and how long the equipment has been used, its performance, any modifications that have been made, and any maintenance and service that has been performed. For example, for a vacuum deposition system, the log should include entries on performance such as ... 

Most vacuum deposition systems are purchased from commercial suppliers. Before specifying a system and the associated fixturing, make sure the processing requirements, examples of which follow, are well defined. 

Flaking of deposited films in an ion plating system is due to thickness buildup, residual film stress, and surface roughness (pinhole flaking). It is exacerbated by the contamination of surfaces by ultrafine particles, which prevent adhesion of the deposited film to surfaces in subsequent deposition runs. This means that an ion plating system probably should be cleaned more often than a sputter deposition or vacuum deposition system. 

Auxiliary plasma (plasma technology) A plasma established in a processing system to assist in some aspect of the processing separate from the main processing event. Examples Plasma cleaning in a vacuum deposition system plasma activation of the reactive gas near the substrate in a reactive magnetron sputter deposition system. 

Thin films of photochromic glass containing silver haUde have been produced by simultaneous vacuum deposition of siUcon monoxide, lead siUcate, aluminum chloride, copper (I) chloride, and silver haUdes (9). Again, heat treatment (120°C for several hours) after vacuum deposition results in the formation of photochromic silver haUde crystaUites. Photochemical darkening and thermal fade rates are much slower than those of the standard dispersed systems. 

Two processes, referred to as sputtered and pyrolitic, were developed to produce large volumes of quality, low-e coated glass. Pyrolitic coatings are incorporated into float glass production and tend to be more durable. Sputtered systems use a stand-alone vacuum deposition process to produce coatings that are have lower emissivities but that are softer and need more protection than pyrolitic coatings. 

The method of thermal vacuum deposition has been used to obtain tin and silicon deposit on TEG surface. The main difficulty at metal component deposition on graphite support is to obtain uniform metal coating on the surface of disperse particles. The system of uninterrupted mixing of TEG powder during the material evaporation has been created. Its principle... 

The advent of a new class of materials systems based on nanoscale particles dispersed or suspended in carrier and/or binders has captured the attention of the microelectronics technical community. These materials provide the opportunity to use inexpensive solution processing equipment versus expensive vacuum deposition equipment commonly used in the microelectronics manufacturing industry. Experts in the microelectronics industry have suggested that over the course of the next live years, the industry will experience a paradigm shift in manufacturing and, more importantly, will enjoy revenue streams created from never-before-seen products based on printed electronics. 

Figure 3.1. Multichamber deposition system for organic light emitting diodes (S sample, RF 02 plasma generator, P vacuum pump, Sh shutter, Q quartz microbalance, C crucibles, M mask for electrode patterning, T tungsten wires for metal deposition).

Nanocarbon emitters behave like variants of carbon nanotube emitters. The nanocarbons can be made by a range of techniques. Often this is a form of plasma deposition which is forming nanocrystalline diamond with very small grain sizes. Or it can be deposition on pyrolytic carbon or DLC run on the borderline of forming diamond grains. A third way is to run a vacuum arc system with ballast gas so that it deposits a porous sp2 rich material. In each case, the material has a moderate to high fraction of sp2 carbon, but is structurally very inhomogeneous [29]. The material is moderately conductive. The result is that the field emission is determined by the field enhancement distribution, and not by the sp2/sp3 ratio. The enhancement distribution is broad due to the disorder, so that it follows the Nilsson model [26] of emission site distributions. The disorder on nanocarbons makes the distribution broader. Effectively, this means that emission site density tends to be lower than for a CNT array, and is less controllable. Thus, while it is lower cost to produce nanocarbon films, they tend to have lower performance. 

Evaporated Al was used by Greber et al (15) as a near UV PCM, followed by Chamberlin and Bergeron (16) in 1974 who used evaporated Si. Subsequently, Havas (17J 8) overcame one of the major process complications of the three - layer system, namely a vacuum deposition of the middle... 

Electrodeposition presents, in principle, several advantages for the investigation and production of layered alloys. Among these are the tendency of electrodeposited materials to grow epitaxial and thus to form materials with a texture influenced by the substrate. Electrodeposition can be used in systems that do not lend themselves to vacuum deposition. The electrodeposition process is inexpensive and can be upscaled with relative ease for use on large parts further, it is a room-temperature technology. This last point may be important for systems in which undesirable interdiffusion between the adjacent layers may readily occur. 

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