AVS 47th International Symposium
    Thin Films Monday Sessions
       Session TF-MoM

Paper TF-MoM3
Atomic Layer Deposition of BN Using Sequential Exposures of BCl@sub 3@ and NH@sub 3@

Monday, October 2, 2000, 9:00 am, Room 203

Session: Atomic Layer Chemical Vapor Deposition I
Presenter: J.D. Ferguson, University of Colorado
Authors: J.D. Ferguson, University of Colorado
S.J. Ferro, University of Colorado
S.M. George, University of Colorado
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BN is an inert insulating material with a very high thermal conductivity that is desirable for many applications. Atomic layer deposition (ALD) is a useful method for growing ultrathin and conformal films. BN ALD was accomplished by separating the binary reaction BCl@sub 3@ + NH@sub 3@ --> BN + 3 HCl into two half-reactions: A) BNH* + BCl@sub 3@ --> BNBCl@sub 2@* + HCl; B) BCl* + NH@sub 3@ --> BNH@sub 2@* + HCl. BN films were grown on high surface area SiO@sub 2@ particles using alternating exposures of BCl@sub 3@ and NH@sub 3@ at 700 K. The sequential surface chemistry was monitored in a vacuum chamber using in situ transmission Fourier transform infrared (FTIR) vibrational spectroscopy. The initial SiO@sub 2@ surface contained SiOH* surface species. The first BCl@sub 3@ exposure reacted with the SiOH* species to form SiOBCl@sub x@* species. The subsequent NH@sub 3@ exposure converted the surface species to BNH@sub 2@*. The following BCl@sub 3@ and NH@sub 3@ exposures converted the surface to BCl@sub x@* and BNH@sub 2@* species, respectively. By repeating the sequential surface reactions, BN bulk vibrational modes on the SiO@sub 2@ particles increased versus number of AB cycles. In addition, spectroscopic ellipsometry studies of BN ALD on Si(100) measured BN growth rates of ~2.5 Å per AB cycle. Transmission electron microscopy also examined the conformality of the BN films on the SiO@sub 2@ particles.