Effect of Prior C, Si and Sn Implantation on the Etch Rate of CVD Diamond

Abstract

Diamond films were implanted with C+, Si+ or Sn+ ions at multiple energies in order to generate a uniform layer of implantation-induced disorder. The implant energies of 60, 180, 330 and 525 keV for C+ ions, 200, 500 and 950 keV for Si+ ions and 750 and 2000 keV for Sn+ ions were selected to give an approximately constant vacancy concentration at depths over the range ∼ 0-0.5 μm. An analysis of the C+ implanted surfaces by Raman spectroscopy has shown an increase in non-diamond or sp2-bonded carbon at doses in the range 5 × 1013 to 5 × 1015 cm- 2. In comparison, a completely non-diamond structure was evident after implantation with either Si+ ions at a dose of 5 × 1015 ions/cm2 or Sn+ ions at ≥ 5 × 1014 cm- 2. For a given dose, the etch rate of the diamond film was shown to increase with the mass of the implanted species in the order of C+, Si+ and Sn+. For a given implant species, the etch rate increased with the implant dose and the ion-induced vacancy concentration. The etch rate of the implanted diamond in various gases decreased in the order of O2, CF4/O2 and CHF3/O2 plasmas.