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Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/10054/11058

Title: Morphology and resistivity of Al thin films grown on Si(111) by molecular beam epitaxy
Authors: JOSHI, N
DEBNATH, AK
ASWAL, DK
MUTHE, KP
KUMAR, MS
GUPTA, SK
YAKHMI, JV
Keywords: aluminum
metallization
surface
si
Issue Date: 2005
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Citation: VACUUM, 79(3-4), 178-185
Abstract: Thin films of aluminium metal with varying thickness between 10 and 200nm were grown on (I 1 1) Si substrates at 250 degrees C under UHV conditions using molecular beam epitaxy (MBE). Grown thin films were characterized by in situ Xray photoelectron spectroscopy, and ex situ X-ray diffraction, atomic force microscopy and temperature-dependent electrical resisitivity measurements. The results showed that (i) films grow via 3D-island Volmer-Weber growth mechanism, (ii) with increasing film thickness the average grain size increases and the coalescence takes place for thickness > 60 nm, and (iii) independent of the thickness, films grow with (111) orientation. The room-temperature value of resistivity contrary to the predictions of existing theoretical models is found to increase monotonically up to a thickness of 40 nm. This anomalous feature was understood in terms of the film morphology, whereby charge transport takes place via variable range hopping (VRH). For film thickness <= 50 nm, the resistivity vs. temperature curves exhibited a metal-to-insulator (M-I) transition at low temperature, and analysis of insulating region supported the 2D-VRH mechanism of charge transport. However, for thickness >= 60 mn the resistivity decreased sharply and the M-I transition disappeared. The bulk value of resistivity (2.59 mu Omega cm) was obtained for thickness > 200 urn. (c) 2005
URI: http://dx.doi.org/10.1016/j.vacuum.2005.03.007
http://dspace.library.iitb.ac.in/xmlui/handle/10054/11058
http://hdl.handle.net/10054/11058
ISSN: 0042-207X
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