Boron nitride thin films have been grown by both laser-assisted, and conventional atomic layer deposition (LALD/ALD) at temperatures in the range 250±750 C. Both the NH 3 and BBr 3 precursors were appreciably dissociated by the ArF excimer laser, and up to 600 C, the growth rate was 100 % higher for the LALD process than for ALD. The films consisted of hydrogenterminated turbostratic BN grains. H 2 was theoretically found to bind as strongly as BBr X and NH X (X = 0±2) to hBN(100) edges. The fresh films were stoichiometric with respect to B and N, and contained low degrees of contamination, but oxidized easily in air.

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Surface reconstructions of unterminated 4H−SiC(0001) surfaces have been investigated theoretically using the first principal density functional theory. A (2 × 1) reconstruction was found for the Si(0001) surface, whereas the C(0001̄) surface retained its initial (1 × 1) structure. The downward relaxation was, on the other hand, much larger for the C surface than for the Si surface. The effects of adsorption of C2H2 (or Si) on the two surfaces were also studied. The adsorbates were then observed to bond strongly to the surfaces of Si(0001) and C(0001̄), respectively. They also influenced the surfaces in the direction of bulk parameters.

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