Boron nitride thin films have been prepared by reacting B2H6 and NH3 in a plasma at 1000ºC on various substrates lying flat on a graphite susceptor in a horizontal tube reactor. Only 4 W rf power at 13.56 MHz were required. Pressures ranged from 0.3 to 0.1 Torr. Transmission and reflection electron diffraction revealed that some crystallites exist within the film. The films were smooth and transparent, and exhibited better crystalline quality than BN films obtained from the same reagents by high-temperature CVD. At a NH3:B2H6 ratio 8.1:1 nearly stoichiometric but slightly boron-rich BN was found by electron microprobe analysis. At a projected gas ratio of 7.1:1, stoichiometric BN should be obtained.