The influences of oxygen ion implantation on the structural and electrical properties of B-doped diamond films

The oxygen ion with a dose of 1014 (called CVDBO14) and 1015 cm− 2 (called CVDBO15) was implanted into boron doped diamond films synthesized in chemical vapor deposition. The structural and electrical properties of different samples were characterized by XPS, Raman spectroscopy and 4-probe resistivity measurements. The results show that oxygen ion exists both in the diamond surface and the subsurface of the films. The FWHM values of CVDBO15 samples are higher than those of CVDBO14 samples, indicating that more damages existed in CVDBO15 samples. The resistivity of CVDBO15 sample series is smaller than those of CVDBO14 sample series, and the film with a larger FWHM value exhibits low resistivity. In the 1150 °C annealed sample, the activation energy decreases from 0.50 eV to 0.39 eV with the oxygen ion dose increasing from 1014 to 1015 cm− 2. It is indicated that oxygen ion and the defects produced by ion implantation give contributions to the conductivity in diamond films. Some surface hydrogen is removed and pi-bonded carbon as well as C–H vibration is formed after annealing, which is also relative to the lower resistivity in the samples.

Research Highlights
► Oxygen ion exists both in the diamond surface and the subsurface of the films.
► Oxygen ion and the defects give contributions to the conduction of diamond films.
► Some surface hydrogen is removed and pi-bonded carbon is formed after annealing.