Electrical contacts to nitrogen incorporated nanocrystalline diamond films

Abstract

The effect of surface plasma treatment on the nature of the electrical contact to the nitrogen incorporated nanocrystalline diamond (n-NCD) films is reported. Nitrogen incorporated NCD films were grown in a microwave plasma enhanced chemical vapor deposition (MPECVD) reactor using CH 4 (1%)/N 2 (20%)/Ar (79%) gas chemistry. Raman spectra of the films showed features at ∼ 1140 cm − 1 , 1350 cm − 1 (D-band) and 1560 cm − 1 (G-band) respectively with changes in the bonding configuration of G-band after the plasma treatment. Electrical contacts to both untreated and surface plasma treated films are formed by sputtering and patterning Ti/Au metal electrodes. Ohmic nature of these contacts on the untreated films has changed to non-ohmic type after the hydrogen plasma treatment. The linear current–voltage characteristics could not be obtained even after annealing the contacts. The nature of the electrical contacts to these films depends on the surface conditions and the presence of defects and sp 2 carbon.