Direct determination of the barrier height of Ti-based ohmic contact on p-type diamond (001)

Although Ti-based ohmic contacts are often used in the fabrication of diamond electronic devices, researches on the barrier height (phi(B)) of this contact are very limited and no consistent values have been reached. In this study, a direct determination of phi(B) was performed using X-ray photoelectron spectroscopy. An array of lint-size Ti/Au ohmic electrodes was made on a lightly boron-doped p-type diamond (001) surface, and C 1 s and Au 4f(7/2) XPS spectra were measured. The peak binding energies of the spectra from the sample and from reference samples were compared, and phi(B) was determined to be -0.63 +/- 0.13 eV for the p-type diamond (001). The result is compared with those of previous works and discussed. Prime novelty statement: The Ti-based ohmic contacts are often used in the fabrication of diamond electronic devices. Although reasonably low specific contact resistances between 10(-5) and 10(-7) Omega cm(2) at room temperature have been obtained for the Ti-based ohmic contacts, the barrier height of the contact has not been determined consistently. In this study, the barrier height of the Ti-based ohmic contact on a p-type diamond (001) is directly determined by X-ray photoelectron spectroscopy to be 0.63 +/- 0.13 eV. (C) 2015 Elsevier B.V. All rights reserved.