Electrical characteristics of CoSi2/n-Si(100) Schottky barrier contacts formed by solid state reaction

The Schottky barrier height (SBH) of CoSi2 contacts formed by solid state reaction of Co, Co/Ti, Ti/Co and Ti/Co/SiO2 on n-Si(1 0 0) substrates has been measured in the temperature range from 80 to 300 K with the use of current- and capacitance-voltage techniques. The forward I-V characteristics are analyzed on the basis of the standard thermionic emission model and the assumption of a Gaussian distribution of the barrier heights. The difference in SBHs determined from the I-V and C-V data is temperature dependent. From this difference, the standard deviation and its temperature coefficient are derived and are in the range of 58-78 meV and -0.07 to -0.14 meV K-1, respectively. The Richardson plots, modified according to the Gaussian distribution model, have a good linearity over the whole temperature range for all samples, The corresponding activation energy is in good agreement with the barrier height determined from the C-V data. The SBH of the CoSi2 contacts grown from Co and Ti bimetallic layers is lower than that grown from a Co layer only. The temperature coefficient of the SBH varies from approximately -0.16 meV K-1 for polycrystalline CoSi2 to similar to0 meV K-1 for epitaxial CoSi2 contacts, thus suggesting different interfacial Fermi level pinning at the CoSi2/Si contacts grown from different multilayer structures. (C) 2000 Elsevier Science Ltd. All rights reserved.