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7206. Patterning with the use of ion-assisted selective deposition
Classified abstracts 7206-7213 cooling through the RTP on the overall stresses induced in the thin layers. The previously unknown coefficient of thermal expansion and the biaxial elastic moduli of the PECVD SiO2 and the evaporated Ti and Pt thin films were determined by in situ stress measurements of the abovementioned structure as well as systems composed of the same thin layers deposited on Si, GaAs, GaP, and InAs substrates. A Katz et al, J Appl Phys, 67, 1990, 6237~246. 23. ION AND PLASMA ASSISTED FILM GROWTH 23 7206. Patterning with the use of ion-assisted selective deposition High bias sputtering in inert argon may be used to selectively deposit thin films on patterned substrates. Simultaneous sputter etching and film deposition will, at the initial stage of film formation, cause a newly discovered interface phenomenon. The sputtering yield of a monoatomic thin film will strongly depend on the underlying bulk substrate. During ion bombardment of a growing ultra-thin film on top of a patterned substrate the film may be preferentially sputter eroded on areas where the sputtering yield of the thin film has the largest value. If a critical balance between deposition rate and sputter erosion rate is selected, actual selective large area deposition may be obtained. No degradation of the pattern was observed after selective deposition. This rules out the possibility of any contribution from local variations in the glow discharge to this selective deposition effect. We will also show that it is possible to predict the selectivity between different substrate materials by simulation of the sputtering yield values of the thin film by Monte Carlo calculations of the collision cascade process. B Gelin et al, Vacuum, 41, 1990, 1074-1076. 23 7207. Thin film preparations by low energy ion beams Low energy ion bombardment effects on fundamental processes of film formation are reviewed by using experimental data of ion cluster beam (ICB) deposition. The results show that the density of nucleation sites, the desorption and adsorption of depositing atoms and the enhancement of adatom migration can be significantly controlled by varying the acceleration voltage. Large single crystal AI(111) films on Si(111) substrates at room temperature were deposited. On Si(100) substrates, only two AI crystal orientations grow in the entire film from the interface to the film surface. These films are unique because the lattice misfit of more than 25% is accommodated at the interface. Atomic resolution TEM analysis clearly shows that the boundary of A1-Si interface changes abruptly without forming any transition layer. I Yamada, Vacuum, 41, 1990, 889-891.
23 7208. Transport processes in plasma assisted deposition of superconducting thin films The composition of plasma sputter-deposited high T~ superconducting films, obtained from YBa2Cu30 7 ~ targets, depends on target substrate distance, plasma pressure, and the impact of secondary electrons and negative ions on the films. To investigate some of these phenomena, we have measured spatially-resolved plasma emission spectroscopy of sputtered excited species and the current due to secondary electrons emitted from the target. Also, Langrnuir probe measurements yield spatially-resolved plasma electron temperatures and density distributions. The data are interpreted in terms of thermalization and diffusion profiles of the sputtered species due to collisional processes. S Athavale et al, Vacuum, 41, 1990, 867 869. 23 7209. Ion-assisting magnetron sources: principles and uses The design and performance of magnetron sources which provide at the substrate not only the flux of sputtered atoms but also fluxes of electrons and ions from the plasma are described. This energetic particle bombardment (which is directed to the substrate by an unbalanced magnetic field design) can be beneficial, as when it is used to ion assist the growth of the depositing thin film, or deleterious, e.g. by providing extra heating. Applications of unbalanced magnetrons to investigate the technology of magnetron sputtering are described. Ion assistance of the growing film increases the biaxial compressive stress in the growing film due to an atomic peening process. The lattice strain produced by the stress can be measured using X-ray diffraction, and can be used to quantify the degree of ion assistance. Effects studied in films of refractory metals include the increase in stress until plastic flow occurs during growth, changes in
preferential orientation, the effectiveness of the different gases Ar and Xe in producing stress, energetic neutral bombardment, and moderation of sputtered atoms. New results are presented here for the temperature dependence of the stress production in molybdenum films. The application of unbalanced magnetrons to industrial deposition processes is discussed. B Window and G L Harding, J Vac Sci Technol, A8, 1990, 1277 1282. 23 7210. Mierostruetural variations in aluminum oxide coatings deposited using a dual beam ion system We have sputter-deposited aluminum oxide coatings using a dual ion beam system with a mixture of argon plus 10% oxygen as the working gas. Ambient substrate temperatures and substrate temperatures of 360°C were maintained. The coatings were deposited at deposition rates between 7 and 10 nm min ~, with and without concurrent ion bombardment from the second ion gun. Substantial variations in the microstructure and the amount of entrained gas in the coatings were observed. The coatings contain a mixture of varying amounts of ~-A1203 and amorphous aluminum oxide. Relatively large, 0.5 #m islands of 7-A1203 crystallites surrounded by an amorphous matrix were observed in coatings deposited onto heated substrates with ion bombardment from the second ion gun during deposition. Coatings bombarded with a second ion beam during deposition contain more argon as determined by energy dispersive X-ray analysis. The Roman spectra exhibited by the coatings suggest a variation in chemical reactivity and/or porosity which depends on the deposition conditions. J K G Panitz et al, J Vac Sci Technol, A8, 1990, 1313-1317. 23 7211. Deposition of Cu film on SiO2 using a partially ionized beam Ion bombardment during deposition can significantly modify the film properties. In the partially ionized beam deposition, ions derived from the depositing material, i.e. the self-ions, are used during deposition. Cu films were deposited on SiO2 substrates at room temperature using 1% Cu self-ions with an energy ranging between 0 4 keV. We studied the microstructures of the Cu films using X-ray diffraction and transmission electron microscopy, measured the impurity level inside the films using secondary ion mass spectrometry, and performed the resistivity measurements using a four point probe. The results indicate that there is an optimum ion energy around 2 keV at which, the integrated X-ray intensity ratio 1(1II)/1(200) reaches its maximum value indicating a strong (111) texture, while the impurity concentration and resistivity are minimum. The correlation between the structural, compositional and electrical properties are discussed in the framework of Mayadas and Shatzkets's theory of grain boundary resistivity. It was suggested that the electron reflection coefficient at the grain boundaries is not a constant and is primarily determined by the impurity concentration and orientation of the Cu films which, in turn, depend on the deposition conditions. P Bai et al, J Vac Sci Technol, A8, 1990, 1465-1469. 23 7212. Formation of silicon-based heterostructures in multichamber integrated-processing thin-film deposition systems This paper describes the formation of heterostructure devices using multichamber integrated-processing thin-film deposition systems: clustered processing-tools with uhv-compatible interchamber transfer. The application of remote plasma-enhanced chemical-vapor deposition (remote PECVD) for the formation of semiconducting and dielectric thin films in several device structures is discussed. Special attention is directed to (i) the deposition conditions required for control of layer and interface chemistry, and (ii) post-deposition-annealing(PDA) for the modification of physical and electronic properties of the individual layers and their interfaces. Due to limitations on in situ patterning, each of the device structures is completed after removal from the cluster. A criterion is proposed for the evaluation of multichamber processing systems that is based on the ability to form multilayer structures with two or more electronically significant interfaces without the removal of the heterostructure from the cluster processing ambient. G Lueovsky et al, J Vac Sci Technol, A8, 1990, 1947 1954. 23 7213. The role of ion-assisted deposition in the formation of diamond-like carbon films The recent interest in diamond-like carbon (DLC) and its special properties and applications has resulted in attempts to deposit such films at greater rates and over larger areas. It is necessary that the new methods 571
23 7208. Transport processes in plasma assisted deposition of superconducting thin films The composition of plasma sputter-deposited high T~ superconducting films, obtained from YBa2Cu30 7 ~ targets, depends on target substrate distance, plasma pressure, and the impact of secondary electrons and negative ions on the films. To investigate some of these phenomena, we have measured spatially-resolved plasma emission spectroscopy of sputtered excited species and the current due to secondary electrons emitted from the target. Also, Langrnuir probe measurements yield spatially-resolved plasma electron temperatures and density distributions. The data are interpreted in terms of thermalization and diffusion profiles of the sputtered species due to collisional processes. S Athavale et al, Vacuum, 41, 1990, 867 869. 23 7209. Ion-assisting magnetron sources: principles and uses The design and performance of magnetron sources which provide at the substrate not only the flux of sputtered atoms but also fluxes of electrons and ions from the plasma are described. This energetic particle bombardment (which is directed to the substrate by an unbalanced magnetic field design) can be beneficial, as when it is used to ion assist the growth of the depositing thin film, or deleterious, e.g. by providing extra heating. Applications of unbalanced magnetrons to investigate the technology of magnetron sputtering are described. Ion assistance of the growing film increases the biaxial compressive stress in the growing film due to an atomic peening process. The lattice strain produced by the stress can be measured using X-ray diffraction, and can be used to quantify the degree of ion assistance. Effects studied in films of refractory metals include the increase in stress until plastic flow occurs during growth, changes in
preferential orientation, the effectiveness of the different gases Ar and Xe in producing stress, energetic neutral bombardment, and moderation of sputtered atoms. New results are presented here for the temperature dependence of the stress production in molybdenum films. The application of unbalanced magnetrons to industrial deposition processes is discussed. B Window and G L Harding, J Vac Sci Technol, A8, 1990, 1277 1282. 23 7210. Mierostruetural variations in aluminum oxide coatings deposited using a dual beam ion system We have sputter-deposited aluminum oxide coatings using a dual ion beam system with a mixture of argon plus 10% oxygen as the working gas. Ambient substrate temperatures and substrate temperatures of 360°C were maintained. The coatings were deposited at deposition rates between 7 and 10 nm min ~, with and without concurrent ion bombardment from the second ion gun. Substantial variations in the microstructure and the amount of entrained gas in the coatings were observed. The coatings contain a mixture of varying amounts of ~-A1203 and amorphous aluminum oxide. Relatively large, 0.5 #m islands of 7-A1203 crystallites surrounded by an amorphous matrix were observed in coatings deposited onto heated substrates with ion bombardment from the second ion gun during deposition. Coatings bombarded with a second ion beam during deposition contain more argon as determined by energy dispersive X-ray analysis. The Roman spectra exhibited by the coatings suggest a variation in chemical reactivity and/or porosity which depends on the deposition conditions. J K G Panitz et al, J Vac Sci Technol, A8, 1990, 1313-1317. 23 7211. Deposition of Cu film on SiO2 using a partially ionized beam Ion bombardment during deposition can significantly modify the film properties. In the partially ionized beam deposition, ions derived from the depositing material, i.e. the self-ions, are used during deposition. Cu films were deposited on SiO2 substrates at room temperature using 1% Cu self-ions with an energy ranging between 0 4 keV. We studied the microstructures of the Cu films using X-ray diffraction and transmission electron microscopy, measured the impurity level inside the films using secondary ion mass spectrometry, and performed the resistivity measurements using a four point probe. The results indicate that there is an optimum ion energy around 2 keV at which, the integrated X-ray intensity ratio 1(1II)/1(200) reaches its maximum value indicating a strong (111) texture, while the impurity concentration and resistivity are minimum. The correlation between the structural, compositional and electrical properties are discussed in the framework of Mayadas and Shatzkets's theory of grain boundary resistivity. It was suggested that the electron reflection coefficient at the grain boundaries is not a constant and is primarily determined by the impurity concentration and orientation of the Cu films which, in turn, depend on the deposition conditions. P Bai et al, J Vac Sci Technol, A8, 1990, 1465-1469. 23 7212. Formation of silicon-based heterostructures in multichamber integrated-processing thin-film deposition systems This paper describes the formation of heterostructure devices using multichamber integrated-processing thin-film deposition systems: clustered processing-tools with uhv-compatible interchamber transfer. The application of remote plasma-enhanced chemical-vapor deposition (remote PECVD) for the formation of semiconducting and dielectric thin films in several device structures is discussed. Special attention is directed to (i) the deposition conditions required for control of layer and interface chemistry, and (ii) post-deposition-annealing(PDA) for the modification of physical and electronic properties of the individual layers and their interfaces. Due to limitations on in situ patterning, each of the device structures is completed after removal from the cluster. A criterion is proposed for the evaluation of multichamber processing systems that is based on the ability to form multilayer structures with two or more electronically significant interfaces without the removal of the heterostructure from the cluster processing ambient. G Lueovsky et al, J Vac Sci Technol, A8, 1990, 1947 1954. 23 7213. The role of ion-assisted deposition in the formation of diamond-like carbon films The recent interest in diamond-like carbon (DLC) and its special properties and applications has resulted in attempts to deposit such films at greater rates and over larger areas. It is necessary that the new methods 571