Atomic layer deposition of boron nitride using sequential exposures of BCl3 and NH3

The atomic layer deposition (ALD) of boron nitride (BN) was demonstrated on ZrO2 particles. The BN ALD was accomplished by splitting the binary chemical vapor deposition reaction, BCl3 + NH3 --> BN + 3HCl, into BCl3 and NH3 half-reactions. BCl3, and NH3 were alternately applied in an ABAB... reaction sequence at 500 K. Fourier transform infrared (FTIR) spectroscopy observed that the O-H stretching vibration of the ZrOH* surface species on the initial ZrO2 particles was removed by the first BCl3 exposure. N-H-2 asymmetric and symmetric stretching vibrations attributed to BNH2* dihydride species and N-H stretching vibrations assigned to B2NH* monohydride species were observed after the subsequent NH3 exposure. The BNH2* and B2NH* species were removed and added after the BCl3 and NH3 exposures, respectively. The surface species were monitored during the first 26 AB cycles. FTIR spectroscopy was also used to monitor the bulk BN vibrational feature that grew progressively throughout the 26 AB cycles. After the 26 AB cycles at 500 K, transmission electron microscopy studies revealed uniform and conformal BN films with a thickness of similar to25 Angstrom on the ZrO2 particles. (C) 2002 Elsevier Science B.V. All rights reserved.