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

•The barrier height of Ti-based ohmic contact on p-type diamond is not determined consistently.•In order to directly determine the barrier height by XPS, an array of μm-size Ti/Au ohmic electrodes was made on a lightly boron-doped p-type diamond (001) surface.•C 1 s and Au 4f7/2 XPS spectra were measured and the barrier height was determined to be ~ 0.63 ± 0.13 eV.

Although Ti-based ohmic contacts are often used in the fabrication of diamond electronic devices, researches on the barrier height (ϕB) of this contact are very limited and no consistent values have been reached. In this study, a direct determination of ϕB was performed using X-ray photoelectron spectroscopy. An array of μm-size Ti/Au ohmic electrodes was made on a lightly boron-doped p-type diamond (001) surface, and C 1 s and Au 4f7/2 XPS spectra were measured. The peak binding energies of the spectra from the sample and from reference samples were compared, and ϕB 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 statementThe 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 Ωcm2 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.

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