Plasma assisted chemical vapour deposition of BN coatings: effect of the experimental parameters on the structure of the films

Abstract Boron nitride (BN) coatings have been deposited in a hot wall PACVD reactor with a capacitive coupling at 13.56 MHz, from BCl 3 /N 2 /H 2 /Ar mixtures. The effect of ion bombardment and the hydrogen content on the nature of the BN phases (determined by Fourier transformed infra-red spectroscopy) is highlighted. Gas phase characterisation is performed by optical emission spectroscopy (OES), mass spectrometry (MS) and electrical measurements. The coatings properties are correlated to the plasma characteristics. It is confirmed that well defined ion bombardment conditions are required for c-BN formation. The hydrogen partial pressure in the gas phase plays another determining role on c-BN formation by its effect on the concentration of reactive species in the plasma and thus on the deposition rate. Hence, in addition to the ionic selective etching of the h-BN sites over the cubic sites commonly reported, a chemical effect (leading to preferential etching or reaction inhibition) due to the presence of the chlorine and atomic hydrogen species at the surface might occur.