Boron nitride films were prepared at 1 atm by r.f. thermal plasma chemical vapour deposition from the gas systems of Ar-BF3-N-2 (or NH3, NF3)-H-2, Ar-BCl3-N-2 (or NH3, NF3)-H-2, and Ar-B2H6-N-2 (or NH3)-H-2. The appearance and the deposition rate of the films changed drastically with the composition of the feed gas. Only from the Ar-BF3-N-2(-NF3) gas, were transparent and smooth films obtained, while from other gas systems, white flaky or powder-like deposits formed. The structure of these films was basically sp(2)-bonded turbostratic BN, and the formation of cubic BN was not confirmed.