| Boron nitride (BN) films were grown by the dissociation of the single-source precursor molecule boron triazide [B(N3)3]. A system was developed to allow continuous production of gas-phase B(N3) 3 for deposition of BN films. B(N3)3 has advantages over other single-source BN film precursors because of its chemical simplicity and its potential to provide mild film deposition conditions. Two viable means of dissociating B(N3)3 for film growth are by collisions with N2(A3sumu+) metastable molecules, and by interactions with an argon plasma.; BN films were deposited by collisions of B(N3)3 with N2(A3sumu+) on many different substrates, at temperatures between 25--300°C. The N2(A3sumu+) molecules carry nearly the same energy as 230 nm photons, which efficiently photolyze B(N3)3, but also provide energy and momentum transfer to the films as they are deposited. Films grown on 300°C substrates react more slowly with air than films deposited at 25°C. The films deposited at 300°C contain sp2-bonded BN, with a B:N ratio near 1:1, and are amorphous. These films contain few infrared active impurities, but do contain considerable amounts of oxygen in the form of O2 from exposure to lab air and diffusion into the film.; BN films were grown by dissociation of B(N3)3 in an Ar plasma at temperatures between 25--400°C. In these experiments, plasma-generated Ar ions provide more momentum transfer to the depositing films than do N2(A3sumu+) molecules. Films deposited by plasma dissociation of B(N3) 3 on 400°C silicon substrates exhibit improved qualities over those deposited by collisions of B(N3)3 with N2(A 3sumu+) and may be polycrystalline. These films contain sp2-bonded BN with a B:N ratio very near 1:1, and very few impurities. These films have a high density for sp2-bonded BN, and are more adherent to substrates and resistant to degradation in air than films deposited with N2(A3sumu +).; Ab initio calculations and experimental data support a hypothesis that B(N3)3 dissociates in the gas-phase to form reactive intermediates. These intermediates self-assemble to form 6-member rings or other sp2-bonded BN clusters prior to film deposition. Hence, gas-phase dissociation of B(N3)3 will prefer deposition of sp2-bonded BN films. |
