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Effect of iodine on electrical conduction in polyvinyl fluoride films
Classified abstracts 5733 5742 anisotropic multiple-layer programme is used to calculate the Fresnel reflection coefficients at various angles of incidence; and an iterative leastsquares algorithm compares the theoretical calculations to the experimental data. The data-fitting process yields the index, the thickness and the anisotropy of the oxide layer and also the index and thickness of the SiOx transition layer. M E Pedinoff et al, AppI Optics, 21 (18), 1982, 3307 3313. 30 5733. Production of high-quality V-coatings. (USA) If during the production of V-coatings the minimal power reflectance is nonvanishing, a remedy can be found in correcting the layer thicknesses in the next production run. Then difficulties arise since the same reflectance can be caused by two different sets of thicknesses. This paper describes a new method for the calculation of these thicknesses while a system is developed to discriminate which of the two sets was actually involved in the (erroneous) earlier result. A detailed example is given based on quartzcrystal monitoring of the process. (Netherlands) d Van der Laan and H J Frankena, Appl Optics, 21 (15), 1982, 2809 2813. 31) 5734. Model calculations of tunnelling and thermal evaporation rate constants relating to field evaporation. (GB) Tunnelling and thermal evaporation rate constants are compared for model potential barriers relating to field evaporation. Previous calculations of the temperature below which tunnelling becomes appreciable are shown to be model dependent. Distinctive features of different shaped barriers are found which might be experimentally observable and this could provide a means to distinguish between charge-hopping, chargedraining and image-hump models of field evaporation. The experimental results of Wada et al, who measured the temperature dependence of the evaporation field of W and Mo at constant evaporation rate, are shown to be consistent with the occurrence of ionic tunnelling below 60 K. David R Kingham, .I Phys D: AppI Phys, 15 [12), 1982, 2537 2544. 30 5735. Effect of iodine on electrical conduction in polyvinyl fluoride films. (G B ) I V characteristics of iodine-doped PVF films (thickness ~ 4 5 pm) in a M P M structure have been investigated. The average values of drift mobility and trapped carrier density estimated from these characteristics have been found to be strongly affected by the presence of iodine. The dependence of current and activation energy on the iodine concentration is explained on the basis of a charge transfer type of interaction between iodine and polymeric molecules. (India) Suresh Chand et al, J Phys D: Appl Phys, 15 (12), 1982, 2499 2503. 3O 5736. On the origin of adsorption stress in thin porous films. (GB) Experiments on the tensile stress produced by the adsorption of polar molecules in porous thin films have been extended from earlier work on water vapour to the effect of a range of polar organic adsorbates on magnesium fluoride films. The observations suggest that the adsorbed molecules undergo a series of activated surface reactions, and that the magnitude of the adsorption stress is a complex function of the molecular structure. (Australia) E H Hirsch, J Phys D: Appl Phys, 15 (10), 1982, 1991-2002. 30 5737. 1981 C R Burch prize-winning entry A new view of field evaporation. (GB) A new view of the field evaporation process is presented. A new, energetically self-consistent, model for the electronic structure of a fieldevaporating ion, which allows for self-energy changes due to large charge transfers, is used. This model is consistent with the occurrence of postionization, for which there is recent experimental evidence and theoretical support. Conventional models of the field evaporation process are reexamined in a novel way. The conclusion of this paper is that field evaporation of an ion occurs by charge-draining out of the first ionization level and results in a singly charged ion and that there is then a fielddependent probability of post-ionization to higher charge states. David R Kingham, Vacuum, 32 (8), 1982, 471 476.
31. S P U T T E R I N G 31 5738. Calculation of the current-voltage pressure characteristics of de diode sputtering discharges. (USA) The relationship between current density, applied voltage, and pressure in 226
dc diode discharges used for sputter deposition has been calculated using a model which considers the electron and ion currents within the cathode dark space. Electrons emitted from the target cause ionization primarily at the interface between the dark space and negative glow and ions crossing the dark space suffer symmetric charge exchange collisions with neutrals. The resulting expression for the characteristic is of the form J - B 2,~ IV, - I/~03'2. where l,~ is tile minimum voltage at which the discharge can be maintained. The values of B and V~ have been obtained by comparison with experimental data for argon and oxygen discharges with a Ta sputtering target. They vary approximately as (pressure) 4,~ and (pressure) 1. respectively. Values of B calculated from the experimental data for J and I~ in argon and oxygen discharges agree with the values obtained from the model and measured values for the dark space distance. Comparison of the model with experimental data gives an estimate of the average value of Townsend's ionization coefficient. (Canada) S Manly el al, ,I ,4ppl Phys, 53 12), 1982, 856 860. 31 5739. Ion beam sputter-deposited diamondlike films. (USA) A single b.rgon ion beam source was used to sputter deposit carbon films on fused silica, copper and tantalum substrates under conditions of sputter deposition alone and sputter deposition combined with simultaneous argon ion bombardment. Simultaneously deposited and ion bombarded carbon films were prepared under conditions of carbon atom removal to arrival ratios of 0, 0.36, and 0.71. Deposition and etch rates were measured for films on fused silica substrates. Resulting characteristics of the deposited films are: electrical resistivity of > 101J~ cm, densities of 2.1 g c m 3 for sputter-deposited fihns and 2.2 g c m 3 for simultaneously sputter-deposited and Ar ion-bombarded films. For ~ 1700/~ thick films deposited by either process and at 5550 A wavelength light the reflectance was 0.2, the absorptance was 0.7, the absorption coefficient was 6.7 x 104 c m - ~, and the transmittance was 0.1. Bruce A Banks and Sharon K Rutledge, J Vac Sci Technol. 21 13), 1982, 807 814. 31 5740. High rate deposition of uniformly thick wear-resistant films onto spherical surfaces. (USA) A method for depositing thin wear-resistant fihns onto spherical substrates is explained. Development of the technique is summarized including description of a special wear test on flats which simulates the spherical closed tribosystem. A unique sputtering machine designed to achieve uniform coatings on spheres and spherical cavities is also discussed. G Sehlossman, .I Vac Sci Teclmol, 211 (4), 1982, 1393 1395. 31 5741. l,ow energy Ar + /on sputtering of liquid and solid indium. (USA) Liquid and solid indium targets were bombarded normally by Ar + ions with energies (F~I) ranging from 17 to 180 eV. The relative differential sputtering yields of the In were measured as a function of E~ and target temperature. At Eo = 107 eV, the relative yield of the liquid In was larger than that of the solid In by about 107;]. The shapes of the yield versus Eo curves for the liquid and solid In were similar. The threshold of sputtering was about 17 eV for both liquid and solid. The effects of surface topography on sputtering yields seemed to be the same for the liquid and solid In. The higher yield of the liquid In is attributed to its lower binding energy. Barry L Hurst and C Burleigh Cooper, J AppI Phys, 53 (9), 1982, 6372 6375. 31 5742. Defects in hydrogenated amorphous silicon-carbon alloy films prepared by glow discharge decomposition and sputtering. (USA) Properties of hydrogenated amorphous silicon-carbon alloy (a-Si~ _~C,:H) films prepared by radio frequency (rf) glow discharge decomposition and rf sputtering have been investigated by means of electron spin resonance (ESR), infra-red absorption, optical absorption, and photoeonductivity measurements. Although the number of C H per C atom [C H]/[C] is larger than that of Si-H per Si atom [Si H]/[Si], the ESR spin density increases greatly with the C content. The increase in tile density of dangling bonds may be related to the fact that the number of H atoms in gathered phase increases with an increase in x. ESR measurements also give useful information about the preferential formation of C or Si dangling bonds and the atomic distribution of Si and C through a compositional dependence of the ,q value. A remarkable feature for a-Si~ ,C,.:H film is that the presence of C atoms in the a m o r p h o u s network makes the Si H bond in a-Si~ ~Cx:H more stable than in ,~-H. (Japan) A Morimoto et al, J Appl Phy.~, 53 (IlL 1982, 7299 7305
31. S P U T T E R I N G 31 5738. Calculation of the current-voltage pressure characteristics of de diode sputtering discharges. (USA) The relationship between current density, applied voltage, and pressure in 226
dc diode discharges used for sputter deposition has been calculated using a model which considers the electron and ion currents within the cathode dark space. Electrons emitted from the target cause ionization primarily at the interface between the dark space and negative glow and ions crossing the dark space suffer symmetric charge exchange collisions with neutrals. The resulting expression for the characteristic is of the form J - B 2,~ IV, - I/~03'2. where l,~ is tile minimum voltage at which the discharge can be maintained. The values of B and V~ have been obtained by comparison with experimental data for argon and oxygen discharges with a Ta sputtering target. They vary approximately as (pressure) 4,~ and (pressure) 1. respectively. Values of B calculated from the experimental data for J and I~ in argon and oxygen discharges agree with the values obtained from the model and measured values for the dark space distance. Comparison of the model with experimental data gives an estimate of the average value of Townsend's ionization coefficient. (Canada) S Manly el al, ,I ,4ppl Phys, 53 12), 1982, 856 860. 31 5739. Ion beam sputter-deposited diamondlike films. (USA) A single b.rgon ion beam source was used to sputter deposit carbon films on fused silica, copper and tantalum substrates under conditions of sputter deposition alone and sputter deposition combined with simultaneous argon ion bombardment. Simultaneously deposited and ion bombarded carbon films were prepared under conditions of carbon atom removal to arrival ratios of 0, 0.36, and 0.71. Deposition and etch rates were measured for films on fused silica substrates. Resulting characteristics of the deposited films are: electrical resistivity of > 101J~ cm, densities of 2.1 g c m 3 for sputter-deposited fihns and 2.2 g c m 3 for simultaneously sputter-deposited and Ar ion-bombarded films. For ~ 1700/~ thick films deposited by either process and at 5550 A wavelength light the reflectance was 0.2, the absorptance was 0.7, the absorption coefficient was 6.7 x 104 c m - ~, and the transmittance was 0.1. Bruce A Banks and Sharon K Rutledge, J Vac Sci Technol. 21 13), 1982, 807 814. 31 5740. High rate deposition of uniformly thick wear-resistant films onto spherical surfaces. (USA) A method for depositing thin wear-resistant fihns onto spherical substrates is explained. Development of the technique is summarized including description of a special wear test on flats which simulates the spherical closed tribosystem. A unique sputtering machine designed to achieve uniform coatings on spheres and spherical cavities is also discussed. G Sehlossman, .I Vac Sci Teclmol, 211 (4), 1982, 1393 1395. 31 5741. l,ow energy Ar + /on sputtering of liquid and solid indium. (USA) Liquid and solid indium targets were bombarded normally by Ar + ions with energies (F~I) ranging from 17 to 180 eV. The relative differential sputtering yields of the In were measured as a function of E~ and target temperature. At Eo = 107 eV, the relative yield of the liquid In was larger than that of the solid In by about 107;]. The shapes of the yield versus Eo curves for the liquid and solid In were similar. The threshold of sputtering was about 17 eV for both liquid and solid. The effects of surface topography on sputtering yields seemed to be the same for the liquid and solid In. The higher yield of the liquid In is attributed to its lower binding energy. Barry L Hurst and C Burleigh Cooper, J AppI Phys, 53 (9), 1982, 6372 6375. 31 5742. Defects in hydrogenated amorphous silicon-carbon alloy films prepared by glow discharge decomposition and sputtering. (USA) Properties of hydrogenated amorphous silicon-carbon alloy (a-Si~ _~C,:H) films prepared by radio frequency (rf) glow discharge decomposition and rf sputtering have been investigated by means of electron spin resonance (ESR), infra-red absorption, optical absorption, and photoeonductivity measurements. Although the number of C H per C atom [C H]/[C] is larger than that of Si-H per Si atom [Si H]/[Si], the ESR spin density increases greatly with the C content. The increase in tile density of dangling bonds may be related to the fact that the number of H atoms in gathered phase increases with an increase in x. ESR measurements also give useful information about the preferential formation of C or Si dangling bonds and the atomic distribution of Si and C through a compositional dependence of the ,q value. A remarkable feature for a-Si~ ,C,.:H film is that the presence of C atoms in the a m o r p h o u s network makes the Si H bond in a-Si~ ~Cx:H more stable than in ,~-H. (Japan) A Morimoto et al, J Appl Phy.~, 53 (IlL 1982, 7299 7305