Bonding, retention and thermal stability of shallow nitrogen in diamond (100) by low-energy nitrogen implantation

We investigate the sub-surface bonding, retention, and thermal stability of nitrogen in diamond (100) implanted with 200 and 800 eV N2+ at room temperature (RT) and 600 °C at an ion dose of 3.4×1014 ions/cm2. Upon 200 eV N2+ implantation at RT and 600 °C, nitrogen is incorporated in the diamond lattice mainly in a C-N/C=N bond bonding configuration alongside a small CN(nitrile-like) component. 800 eV N2+ implantation at both RT and 600 °C, the implanted nitrogen can occupy multiple bonding configurations, including C-N/C=N and CN(nitrile-like) bonds. Implantation at 600 °C resulted in higher thermal stability of the implanted nitrogen compared to RT implantation due to dynamic annealing assisted defect curing and desorption of weekly bonded species (possibly nitrogen bonded to defects) during the high temperature implantation. The long-range order of the N2+ implanted diamond surfaces was also investigated using low-energy electron diffraction measurements.