Phase formation of boron nitride thin films under the influence of impurity atoms

摘要

Boron nitride thin films have been prepared via mass selected ion beam deposition (MSIBD) by alternating deposition of 11{sup left}B{sup}+, 14{sup left}N{sup}+ and 31{sup left}P{sup}+ ions with ion energies between 200 and 500 eV and substrate temperatures ranging from 200 to 280 ℃. The phase formation as a function of the P{sup}+ ion fraction was studied using infrared absorption spectroscopy (FTIR). The thresholds of substrate temperature and ion energy, which are required to nucleate cubic boron nitride using MSIBD are shifted to higher values with increasing P content. Electrical measurements showed Frenkel-Poole emission as conduction mechanism but without any apparent dependence of the phosphorous content on the conductivity. X-ray photoelectron spectroscopy was applied to probe the B, N and P core-level states, indicating a substitution of nitrogen atoms by phosphorous and formation of B-P bonds.