Surface Brillouin scattering on annealed ion-implanted CVD diamond

• An a-C layer was created by carbon ion implantation into diamond and annealing.
• A 50 nm diamond layer created near the surface has no SAW modes signature.
• Changes in SBS were observed after annealing at 600 and 1000 °C.
• The a-C layer is a material that is harder than graphite and softer than diamond.

Single crystal <100> diamond samples were implanted with a total fluence of 1.5 × 1016 ions/cm2 at single energy of 150 keV using carbon ions. This implantation fluence created a damage density that would not restore the diamond structure after annealing. Surface Brillouin scattering studies show that the elastic properties of the highly damaged diamond layer starts to transit from diamond-like to amorphous carbon state at an annealing temperature of 500 °C. The amorphous carbon layer is shown to have a sound velocity (elastic properties) similar to those reported for tetrahedral amorphous carbon (ta-C). Raman spectroscopy, EELS and HRTEM has been used in conjunction with the SBS data to monitor the changes in the carbon implanted diamond at different annealing temperatures.