Diffusion effects and nucleation of thin film boron nitride growth from borazine on the Si(100) surface

Time-of-flight (TOF) direct recoiling (DR) studies of borazine (B 3N3H6) decomposition on the Si(100) surface between 100 and 850°C are reported. The DR method with a grazing incidence angle directly detects the diffusion of light adsorbate elements into sites below the first Si layer, and this migration process is examined here as a function of temperature (T). Submonolayer coverages of coadsorbed B and N atoms (from B3N3H6) occupy subsurface sites after annealing above 550°C. The B + N results are compared with the well-studied N atom (from NH3) case and limited data for boron from B 10H14. The atomic composition of the initial growth surface during thermal chemical vapor deposition (CVD) of boron nitride (BN) from B3N3H6 is surveyed in situ as a function of T using DR in a B3N3H6 flux of 4×1016 molecules cm-2 s-1. Desorption of surface hydrogen plays a central role in controlling both the submonolayer diffusion effects and thermal CVD growth of BN.