BN films were deposited using hot wall CVD with two different boron precursors, TMB(B(CH3)3) (99.99% purity, Voltaix/Air Liquide Advance Materials, FL) and TEB (B(C2H5)3) (semiconductor grade quality, from SAFC Hitech). The precursor used for N was ammonia (NH3, 99.999%, further purified using a getter filter) with H2 (palladium-membrane purified) as the carrier gas. The B precursors, in their respective processes, were added through a separate quartz liner along with H2 to suppress the formation of adducts between the precursors. A pyrometer (Heitronics KT81R, calibrated using a silicon melt test) was used to monitor the growth temperature. The process pressure was maintained using a throttle valve before the process pump. Process parameters were selected from past studies on TEB and TMB. For both processes, the base pressure was kept below 2 x 10 -2 mbar. Carrier gas flow was maintained at 5000 sccm H2.