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 CoSi2/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.