Carbon incorporation in boron nitride grown by MOCVD under N2 flow

Boron Nitride (BN) films were grown on 2-inch sapphire substrates using metal organic chemical vapour deposition (MOCVD) using two different carrier gases, nitrogen and hydrogen. Structural properties of grown BN films were systematic investigated. SIMS measurements reveal that BN films grown under nitrogen flow are strongly carbon contaminated, predominantly in a form of carbon clusters. It is shown that carbon contamination originates from reactions in which TEB precursor is involved. It is also shown that hydrogen eliminates excess of unreacted carbon. Thus, the MOCVD growth of BN films under H2 flow is leading to carbon free layers with atomically smooth surface morphology.