93-96. Original Russian Text Copyright © 2005 by Bruk, Zhikharev, Grigor'ev, Spirin, Kal'nov, Kardash. 1 During the last fifteen years, a new area of microelectronics and nanotechnology, the image formation of solid substrates by sharply focused electron beam deposition from a vapor of organometallic (or other metal-containing) precursors have been intensively developed [1][2][3][4]. This technique makes it possible to apply with nanometer-scale accuracy 2D and 3D images with quite various (conducting, dielectric, emission, optical, sensor, etc.) properties of their elements. The deposition of iron-based materials by means of this technique is of considerable interest (in particular, from the viewpoint of magnetic properties). One of the most appropriate iron precursors is triiron dodecacarbonyl Fe 3 ( CO ) 12 (IDC), which is an intermediate of the thermal degradation of iron pentacarbonyl. However, no works on imaging with the use of this precursor have been performed.In this paper, we present preliminary results on image formation by deposition from IDC.EXPERIMENTAL Deposition was carried out in a Camscan scanning electron microscope at an electron energy E of 15 or 20 keV, a beam current I of 5-200 nA, and an IDC pressure ( p ) of 1-10 -5 Pa. The diameter of a focused electron beam was 0.2-0.5 µ m, the width of deposited lines (at half maximum) was 1 to 2 µ m, and the line height was 50-80 nm. The lines were deposited on singlecrystal silicon wafers coated with an Si 3 N 4 surface layer 1 E-mail: bruk@cc.nifhi.ac.ru of 0.2 µ m in thickness, on which gold electrodes were evaporated. The distance between the electrodes was 9 µ m, the length of a deposited line was about 13 µ m, and the pixel time was 20 ms. The values of current density in an incident electron beam were ~0.1-10 A/cm 2 . The electric resistance of deposited lines was measured with an integrated digital device Shch-300.
RESULTS AND DISCUSSIONWe studied the dependence of the electric resistance R of deposited lines on the beam current during deposition, IDC vapor pressure, deposition time, and other parameters. It was found that depending on deposition conditions, R varied from 4 k Ω to 100 M Ω . As the beam current increases, R rapidly decreases. When I varies by a factor of 20-30, R changes approximately by four orders of magnitude (Fig. 1). The dependence of R on the deposition time τ is illustrated in Fig. 2. Additional irradiation of high-resistance lines (preliminarily deposited at low I values) at high I values leads to a considerable increase in the conductivity of lines.The short-term (for 10 min) heating at 170°ë of the lines deposited at room temperature practically does not alter their conductivity after cooling to room temperature. This refers to both low-and high-resistance lines. Note that according to published data [5], IDC effectively decomposes at temperatures about 150°ë yielding reduced iron. Hence, it follows that the deposited material does not contain intact IDC.Using scanning-force microscopy, the cross section of depo...
