Effect Of Deposition Conditions Research Articles

Effect of Deposition Conditions on Intrinsic Stress in a-Si: H Films

Intrinsic stress in the a-Si: H film, which reflects the internal microstructure of the film under deposition and thus gives the information about the construction of amorphous network, has been evaluated by the Baser interferometric method. The intrinsic stress induced in the a-Si: H film is compressive and increases with the deposition temperature. As the intrinsic compressive stress is increased, decreases are observed in the deposition rate, the total hydrogen concentration, and the ratio of hydrogen concentration with the configuration SiH2, SiH3, and (SiH2)n to that with SiH. These results on the temperature dependence of a-Si: H film growth indicate that the contribution of excited species in the plasma to the growth of the a-Si: H is restricted by the intrinsic compressive stress induced in the a-Si: H through differences in molecular dimensions of the excited species.

Role of deposition conditions, impurities and structural defects in the epitaxial growth of thin films

A summary of the theoretical and experimental investigations carried out to understand the problem of epitaxy is given. The effect of deposition conditions and the nature of the substrate-deposit combination on the orientation of the final film is discussed. The importance of the nucleation and growth stages, reorientation and recrystallization effects and the influence of the impurities and defects in the substrate surface on the quality of the films deposited are presented.

Fabrication of thin wall cylindrical shells by sputtering

In this paper we describe the process used to grow thin wall cylindrical shells by sputtering. The shells are grown on both sacrificial aluminum and reusable stainless steel mandrels. The post-deposition process used to remove the shells from the mandrels is described. The effects of deposition conditions and post-deposition treatment on crystallographic structure are presented. Comparisons of sputtered shells are made with conventionally machined shells with respect to crystallography, dimensional uniformity and performance. Some test results of sputtered thin wall cylindrical shells used as pressure-sensing elements are given.

Reverse osmosis characteristics of composite membranes prepared by plasma polymerization of allylamine. Effects of deposition conditions

A study has been conducted to determine the effects of flow configuration and reaction conditions on the performance of composite reverse osmosis membranes prepared by plasma polymerization of allylamine over a porous polymer substrate. It was established that superior membranes were obtained by using a gas-flow configuration avoiding direct monomer flow over the substrate. High rejections of NaCl could be attained when the plasma-deposited film was sufficiently thick to bridge all of the pores in the substrate. It was observed that in addition to influencing the rate of polymerization, the conditions used to sustain the plasma also affected the reverse osmosis characteristics of the deposited film. The effects of these conditions and other preparation procedures are discussed. Attempts to use infrared spectroscopy and ESCA to identify the relationship between polymer structure and reverse osmosis performance were not successful. ESCA did prove useful, though, in confirming an earlier postulated hypothesis that degradation of reverse osmosis performance is associated with the hydrolysis of nitrogen-containing structures in the plasma-deposited film.

Deposition of semiconductor films with high solar absorptivity

Thin films of narrow−gap (∠0.6 eV) semiconductors should be good selective solar absorbers since they absorb in the solar spectrum (<2 μ) but transmit in the infrared (≳2 μ). Unfortunately, semiconductors have high indices of refraction which give high reflectivity from smooth surfaces and thus have poor solar−absorbing efficiency. In this investigation, the effect of deposition conditions on surface morphology and solar absorptivity of silicon, germanium, and lead sulfide thin films is examined. It is found that the solar absorptivity of germanium films can be greatly increased by ’’gas evaporating’’ them in a low−pressure (20 mTorr) argon atmosphere apparently due to changes in the film−surface morphology. Solar absorptances of greater than 95% are obtained from 1−μ thick films of gas−evaporated germanium and vacuum−evaporated PbS films. Gas−evaporated silicon films showed a shift in the absorption edge which makes them unacceptable for solar absorbers.

Aluminum alloy film deposition and characterization

A flash evaporation system which utilizes a mechanism for feeding alloy wire onto a heated bar was used for the deposition of aluminum-silicon, aluminum-copper and aluminum-copper-silicon. The effect of deposition conditions and processing procedure on film composition and microstructure was determined. Particular attention was given to the film surface topography and the possible influence of deposition conditions, alloy composition, substrate type, thickness, annealing time and temperature and addition of oxide overlayers. Resistivity, and possible shorting of junctions in silicon as a consequence of silicon dissolution in the metallization, were considered as a function of alloy composition. Metal continuity over steps in the substrate was tested as a function of deposition temperature. These studies yielded recommendations, regarding the general use of alloy metallization on silicon devices and its specific use in two-level metallization configurations, which include: deposition at temperatures down to 275°C and at evaporation rates of about 0.4 g/min; the use of initial layer thickness down to 0.7 μ; post-deposition processing for aluminum-copper or aluminum-copper-silicon not to exceed 525°C; the addition of 1% silicon to prevent junction penetration; and the addition of 4% copper to lend adequate electromigration resistance and inhibit hillock growth during high temperature processing.

Evaporation of Antimony Trisulfide in Ar Gas and Its Evaporated Films

Antimony trisulfide was evaporated in Ar gas at low pressure, and the effects of deposition conditions on the physical properties of evaporated films were studied. The deposition parameters such as Ar pressure, evaporation rate, evaporation source temperature, and the distance between a substrate and an evaporation source temperature, exercised a great effect on the properties of evaporated films.The effects of deposition parameters revealed in this experiment were very different from those observed in the vacuum deposition of antimony trisulfide. This shows the deposition mechanisms in Ar at low pressure are different from the ordinary vacuum deposition mechanisms.In this paper, those mechanisms are briefly discussed and qualitative explanations are given.

62. Effects of deposition conditions and heat treatment on the properties of pyrolytic carbon

62. Effects of deposition conditions and heat treatment on the properties of pyrolytic carbon

Titanium-dioxide dielectric films prepared by vapor reaction

The high dielectric constant of TiO 2 and its low sensitivity to temperature and frequency make TiO 2 attractive for integrated electronic applications. The most useful technique for preparing titanium-dioxide films on semiconductors and metals is the vapor reaction process. The apparatus developed for film preparation is described, and effects of deposition conditions are discussed. Uniform films are obtained over large areas and film thickness is readily controlled. Films have dielectric constants up to 82 and dissipation factors between 0.008 and 0.03 at 1 kc and a dc leakage resistivity of 5×1012ohm/cm. The dielectric constant is relatively frequency insensitive into the gigacycle range.