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New thin film techniques for microelectronics and optical applications
Abstracts
Interfacial reactions in thin film couples V Marinkovi6, Department of Metallurgy, Faculty of Natural Science and Technology, and Institute J. Stefan, E. Kardelj University, Ljubljana, Yugoslavia
of the coatings at elevated temperatures. Sputtering, e.g. provides a simple means to produce such insoluble alloys because of the possibility of mixing the constituents in the gas phase. The work to be presented here was done by high rate sputtering with a new cylindrical magnetron sputtering source. The resulting coatings exhibit outstanding fatigue and wear properties as well as excellent adhesion. Bearings for combustion engines coated in this way surpassed their best conventional counterparts in terms of lifetime by a factor larger than 3. Finally, future aspects considering economy, choice of further materials and coating technologies are discussed.
A modern microelectronic device is a complex multicomponent system containing several different materials separated by interfaces. The long-term stability of such a device often critically depends on the nature and extent of interdiffusion and reaction driven by chemical nonequilibrium between the layers. Due to the geometrical and microstructural characteristics of thin-film structures these equilibrating processes can significantly affect the composition and microstructure of a large part of the entire thin film structure even at moderate temperatures and for short periods of service. The obvious technological importance of these phenomena greatly intensified research of interdiffusion in thin film couples. As a result of this, new phenomena in thin film interdiffusion were found that were not apparent in bulk interdiffusion studies as, e.g. sequential formation of intermetallic compounds, and occurrence of metastable or nonequilibrium compounds due to their stabilization by interfacial or diffusional constraints. Due to such unique features of thin film reactions, and since the equilibrium phase diagrams can given only clues to the phenomena that are likely to occur, several empirical rules have been formulated by different authors. These make possible the prediction of some characteristics of thin film reactions, e.g. the lowest reaction temperature and the phase which nucleates first in a thin film couple. However, the details of the sequence of the phase formation, as well as some of the mechanisms of relaxation of internal stresses which accompany interdiffusion and reaction in thin film couples are far from being well understood. In this review, some examples from literature are presented which illustrate some of the more pertinent features of thin film reactions.
The interaction CF water with solid surfaces : fundamental aspects
Soft metallic tribological coatings
T E Madey, National Bureau of Standards, Gaithersburg, MD 20899, USA
W Giirtner, Miba Gleitlager AG, A-4663 Laakirchen, Austria High rate deposition technologies introduce thin films to mechanical engineering problems. One of these new developments is soft coatings which is used to improve tribological properties between gliding components in all kinds of engines. Such soft coatings are used not only where a reduction in friction and wear is required but also a high reliability in operation and the protection of a high quality component part has to be ensured. An example for such an application is the overlay of sliding bearings. The requirements for these films are in themselves contradictory. On the one hand the overlay should have as high fatigue strength and wear resistance as possible, but on the other hand good conformability and dint embeddability are necessary. Moreover, high seizure resistance and resistance to corrosion are also required. The fundamental structure of such coatings is a heterogeneous one. A soft low melting component is suspended in a tough, but not brittle, matrix. The soft particles provide low friction and good embeddability and the matrix ensures the mechanical and wear properties. Favourable materials are insoluble alloy systems (e.g. Al-Sn, AIPb, Ag-Pb and Cu-Pb), because in this way it is obviously possible to exclude the formation of intermetallic phases, which would alter the properties 224
New thin film techniques for microelectronics and optical applications C Misiano, SELENIA, Research Department Via Tiburtina, P.O.B. 7083, 0010 Roma, Italy The new trends in physical vapour deposition (P.V.D.) are discussed and in particular the following ion-assisted P.V.D. techniques are considered: (i) ion beam sputtering deposition; (ii) ion plating plasma assisted (low energy); and (iii) ion plating plasma assisted (high energy); (iv) ion plating ion beam assisted. The results obtained by means of these processes are described in comparison with the conventional evaporation and sputtering techniques. The most important foreseeable applications in hybrid microelectronics, optical coatings and integrated optics are discussed and in particular: (i) low loss optical coatings; (ii) high power laser coatings and (iii) metallization of alumina substrates. Finally some interesting forecasts for the industrial applications of these new techniques are reported.
Recent experimental and theoretical results concerning the interaction of H20 with solid surfaces will be presented. Emphasis will be on studies involving well-characterized single crystals of metals, oxides and semiconductors. We will discuss the factors which influence dissociation vs associative (molecular) adsorption pathways. When H20 adsorbs molecularly, it tends to form three-dimensional hydrogen-bonded clusters, even at fraction monolayer coverages, because the strength of the attractive interaction between molecules is comparable to that of the substrateH20 bond. The template effect of the substrate is important in determining both the local and long-range order of HzO molecules in these clusters. The influence of surface additive atoms (e.g. O, Br, Na, K) on the surface structure and chemistry of H20 is examined.
Surface engineering using ion beams J S Colligon, Centre for Thin Film and Surface Research, The
University of Salford, Salford M5 4 WT, UK This paper attempts to review the development of ion-surface engineering and to highlight the most recent applications. Ion
Interfacial reactions in thin film couples V Marinkovi6, Department of Metallurgy, Faculty of Natural Science and Technology, and Institute J. Stefan, E. Kardelj University, Ljubljana, Yugoslavia
of the coatings at elevated temperatures. Sputtering, e.g. provides a simple means to produce such insoluble alloys because of the possibility of mixing the constituents in the gas phase. The work to be presented here was done by high rate sputtering with a new cylindrical magnetron sputtering source. The resulting coatings exhibit outstanding fatigue and wear properties as well as excellent adhesion. Bearings for combustion engines coated in this way surpassed their best conventional counterparts in terms of lifetime by a factor larger than 3. Finally, future aspects considering economy, choice of further materials and coating technologies are discussed.
A modern microelectronic device is a complex multicomponent system containing several different materials separated by interfaces. The long-term stability of such a device often critically depends on the nature and extent of interdiffusion and reaction driven by chemical nonequilibrium between the layers. Due to the geometrical and microstructural characteristics of thin-film structures these equilibrating processes can significantly affect the composition and microstructure of a large part of the entire thin film structure even at moderate temperatures and for short periods of service. The obvious technological importance of these phenomena greatly intensified research of interdiffusion in thin film couples. As a result of this, new phenomena in thin film interdiffusion were found that were not apparent in bulk interdiffusion studies as, e.g. sequential formation of intermetallic compounds, and occurrence of metastable or nonequilibrium compounds due to their stabilization by interfacial or diffusional constraints. Due to such unique features of thin film reactions, and since the equilibrium phase diagrams can given only clues to the phenomena that are likely to occur, several empirical rules have been formulated by different authors. These make possible the prediction of some characteristics of thin film reactions, e.g. the lowest reaction temperature and the phase which nucleates first in a thin film couple. However, the details of the sequence of the phase formation, as well as some of the mechanisms of relaxation of internal stresses which accompany interdiffusion and reaction in thin film couples are far from being well understood. In this review, some examples from literature are presented which illustrate some of the more pertinent features of thin film reactions.
The interaction CF water with solid surfaces : fundamental aspects
Soft metallic tribological coatings
T E Madey, National Bureau of Standards, Gaithersburg, MD 20899, USA
W Giirtner, Miba Gleitlager AG, A-4663 Laakirchen, Austria High rate deposition technologies introduce thin films to mechanical engineering problems. One of these new developments is soft coatings which is used to improve tribological properties between gliding components in all kinds of engines. Such soft coatings are used not only where a reduction in friction and wear is required but also a high reliability in operation and the protection of a high quality component part has to be ensured. An example for such an application is the overlay of sliding bearings. The requirements for these films are in themselves contradictory. On the one hand the overlay should have as high fatigue strength and wear resistance as possible, but on the other hand good conformability and dint embeddability are necessary. Moreover, high seizure resistance and resistance to corrosion are also required. The fundamental structure of such coatings is a heterogeneous one. A soft low melting component is suspended in a tough, but not brittle, matrix. The soft particles provide low friction and good embeddability and the matrix ensures the mechanical and wear properties. Favourable materials are insoluble alloy systems (e.g. Al-Sn, AIPb, Ag-Pb and Cu-Pb), because in this way it is obviously possible to exclude the formation of intermetallic phases, which would alter the properties 224
New thin film techniques for microelectronics and optical applications C Misiano, SELENIA, Research Department Via Tiburtina, P.O.B. 7083, 0010 Roma, Italy The new trends in physical vapour deposition (P.V.D.) are discussed and in particular the following ion-assisted P.V.D. techniques are considered: (i) ion beam sputtering deposition; (ii) ion plating plasma assisted (low energy); and (iii) ion plating plasma assisted (high energy); (iv) ion plating ion beam assisted. The results obtained by means of these processes are described in comparison with the conventional evaporation and sputtering techniques. The most important foreseeable applications in hybrid microelectronics, optical coatings and integrated optics are discussed and in particular: (i) low loss optical coatings; (ii) high power laser coatings and (iii) metallization of alumina substrates. Finally some interesting forecasts for the industrial applications of these new techniques are reported.
Recent experimental and theoretical results concerning the interaction of H20 with solid surfaces will be presented. Emphasis will be on studies involving well-characterized single crystals of metals, oxides and semiconductors. We will discuss the factors which influence dissociation vs associative (molecular) adsorption pathways. When H20 adsorbs molecularly, it tends to form three-dimensional hydrogen-bonded clusters, even at fraction monolayer coverages, because the strength of the attractive interaction between molecules is comparable to that of the substrateH20 bond. The template effect of the substrate is important in determining both the local and long-range order of HzO molecules in these clusters. The influence of surface additive atoms (e.g. O, Br, Na, K) on the surface structure and chemistry of H20 is examined.
Surface engineering using ion beams J S Colligon, Centre for Thin Film and Surface Research, The
University of Salford, Salford M5 4 WT, UK This paper attempts to review the development of ion-surface engineering and to highlight the most recent applications. Ion