The atomic layer deposition (ALD) of boron nitride (BN) was demonstrated on ZrO particles. The BN ALD was accomplished 2 by splitting the binary chemical vapor deposition reaction, BCl qNH TMBNq3HCl, into BCl and NH half-reactions. BCl and 3 3 3 3 3 NH were alternately applied in an ABAB« reaction sequence at 500 K. Fourier transform infrared (FTIR) spectroscopy observed 3 that the O–H stretching vibration of the ZrOH* surface species on the initial ZrO particles was removed by the first BCl 2 3 exposure. N–H asymmetric and symmetric stretching vibrations attributed to BNH * dihydride species and N–H stretching 2 2 vibrations assigned to B NH* monohydride species were observed after the subsequent NH exposure. The BNH * and B NH* 2 3 2 2 species were removed and added after the BCl and NH exposures, respectively. The surface species were monitored during the 3 3 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 ;25 A on the ZrO particles. 2 ̊ 2002 Elsevier Science B.V. All rights reserved.