Kinetics of silicide formation measured by in situ ramped resistance measurements

Abstract

The use of ‘‘Kissinger’’ plots to analyze in situ resistance monitoring of thin-film reactions during heating at a constant rate is widely accepted. One obtains the activation energy for diffusion, at least in the case of diffusion-controlled reactions. The aim of this article is to extend the analysis one step further and show that, provided that the thickness of the layers formed is known, the same experimental and analytical techniques may yield the pre-exponential growth factor. The validity of the procedure is demonstrated by comparing the results thus obtained with data from the literature derived by conventional analysis of compound growth during isothermal annealing. Such comparisons have been made for Co2Si, CoSi, CoSi2, Pt2Si, PtSi, Ni2Si, and NiSi formation on undoped polycrystalline Si and single-crystal Si on sapphire substrates with ramp rates ranging from 10−2 °C/s to 102 °C/s. Measurements used both conventional furnace and rapid thermal annealing. In the past, the common practice has been to use the Kissinger method regardless of the sequence of growing phases. However, for phases other than the first one to be formed the direct Kissinger analysis needs to be modified. In the present cases the results obtained by means of an appropriately corrected procedure are not significantly different; that may not always be true.