Oriented Graphitic Carbon Film Grown by Mass-Selected Ion Beam Deposition at Elevated Temperatures
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ic Carbon Film Grown by MassSelected Ion Beam Deposition at Elevated Temperatures J. Kulik, G. Lempert, E. Grossman and Y. Lifshitz MRS Proceedings / Volume 593 / 1999 DOI: 10.1557/PROC593305
Link to this article: http://journals.cambridge.org/ abstract_S194642740016779X How to cite this article: J. Kulik, G. Lempert, E. Grossman and Y. Lifshitz (1999). Oriented Graphitic Carbon Film Grown by MassSelected Ion Beam Deposition at Elevated Temperatures. MRS Proceedings,593, 305 doi:10.1557/PROC593305 Request Permissions : Click here
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ORIENTED GRAPHITIC CARBON FILM GROWN BY MASS-SELECTED ION BEAM DEPOSITION AT ELEVATED TEMPERATURES J. KULIK*, G. LEMPERT**, E. GROSSMAN**, and Y. LIFSHITZ** *Texas Center for Superconductivity, University of Houston, Houston, Texas 77204-5932 **Soreq Nuclear Research Center, Yavne 81800, Israel ABSTRACT Mass-selected ion-beam deposition using 120 eV C' ions has been used to grow a carbon film on a Si substrate held at 2000 C. The structure of the film has been characterized by transmission electron microscopy and electron energy loss spectroscopy. The film is graphitic and highly oriented with the c-axis lying parallel to the substrate. Moreover, the film is under significant biaxial stress such that the graphitic layer spacing is reduced by 4% from that of ambient pressure graphite. This oriented structure evolves due to the mobility of the carbon atoms at 200 'C. The material is sufficiently crystalline on the nanometer scale so as to produce Bragg diffraction discs in a convergent beam electron diffraction pattern using a 2.5 nm probe. INTRODUCTION Intrinsic compressive stress in thin films is known to arise from the use of hyperthermal species in the film deposition process. Use of such energies for film growth, and especially for carbon, has received considerable attention since the original work of Aisenberg and Chabot [I]. With energies in the range of about 10 to 1000 eV, impinging species undergo a shallow implantation process (subplantation) that allows incorporation of atoms into the subsurface layers of the growing film resulting in densification and significant levels of biaxial stress [2-6]. Investigators now understand that the interesting and desirable properties of these carbon films, such as high hardness and density, are controlled largely by choice of deposition energy. For example, room temperature deposition with energies from 50 eV to 300 eV [6,7] results in 3 amorphous films that are 80 - 85% sp bonded and possess many diamond-like properties. It is
the shallow implantation process that is crucial both to the incorporation of the impinging carbon ions or atoms into the subsurface layers of the growing film and to the resulting biaxial stress and densification of the final film. Researchers now generally accept that high levels of biaxial stress are essential for the stabilization of tetrahedral bonding in carbon. Partial or complete removal of this stress occurs
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