CHARACTERIZATION OF BORON-NITRIDE THIN-FILMS PREPARED FROM A POLYMER PRECURSOR

Excellent quality boron nitride (BN) thin films on silicon have been p roduced by a simple procedure involving spincoating solutions of the ' 'single-source'' polymeric-precursor polyborazylene, (B3N3H similar to (4))(x), on a silicon substrate, followed by pyrolysis at 900 degrees C, Rutherford backscattering spectrometry (RBS) indicates that the B/N ratios are 1.37 and 1.09 for conversions carried out in a vacuum oven at 900 and 1250 degrees C, respectively. Forward recoil spectrometry (FRES) showed that the atomic percent of residual hydrogen is 10 and 9 %, respectively, Plain-view and cross-sectional scanning electron micr oscopy (SEM) studies showed that the samples annealed at 900 degrees C were clean and uniform in thickness, A thickness of 800 x 10(15) atom s/cm(2) was determined by ion scattering. Films annealed to 1250 degre es C likewise showed a continuous unbroken boron nitride layer, but al so exhibited morphological features resulting from reactions of the un derlying silicon oxide-silicon interface in the substrate. Auger elect ron spectroscopy and atomic force microscopy showed that the BN coatin g produced at this higher temperature remained unbroken but had a surf ace area of similar to 15% covered by dimples 2-7 nm in depth. Compare d to typical films made by chemical vapor deposition, BN films produce d from this ''single-source'' method have lower hydrogen and carbon co ncentrations.