Increased effective barrier heights in Schottky diodes by molecular-beam epitaxy of CoSi2 and Ga-doped Si on Si(111)

Abstract

Increasing the effective Schottky-barrier height of epitaxial CoSi 2/Si(111) diodes by the use of thin, highly doped Si layers in close proximity to the metal-semiconductor interface has been studied. Intrinsic Si, Si doped by coevaporation of Ga, and epitaxial CoSi2 layers have all been grown in the same molecular-beam epitaxy system. Current-voltage and photoresponse characterization yield barrier heights ranging from 0.61 eV for a sample with no p+ layer to 0.89 eV for a sample with a 20-nm-thick p+ layer. These results are compared to theoretical values based on a one-dimensional solution of Poisson's equation under the depletion approximation.