We review the growth behavior of epitaxial ZrB 2(0001) films on Si(111) via the thermal decomposition of the unimolecular precursor Zr(BH 4) 4 studied in situ by low-energy electron diffraction and low-energy electron microscopy, and ex situ by cross-sectional transmission electron microscopy and atomic force microscopy. Under appropriate kinetic conditions, epitaxy was achieved in spite of the very large lattice mismatch between ZrB 2(0001) and Si(111). The growth was followed from the initial nucleation stage to the final epitaxial film at various growth temperatures. At 900°C, the growth of ZrB 2(0001) proceeded by the nucleation of two-dimensional islands. These islands eventually coalesced to form a continuous atomically smooth film. The interface between ZrB 2(0001) and Si(111) was modeled theoretically and the most favorable interface consisted of the ZrB 2(0001) growing on a Si(111)-(√3 × √3)B surface with the Zr layer nearest to the interface and the B layer on the top surface. The in-plane a lattice parameter of the ZrB 2(0001) surface has a perfect match with that of Al xGa 1-xN where x = 0.26. Epitaxial layers of Al 0.2Ga 0.8N grown on a ZrB 2/Si(111) substrate by metalorganic chemical vapor deposition (MOCVD) exhibit luminescence properties comparable to or better than those from layers of identical composition grown on sapphire substrates.
|Original language||English (US)|
|Number of pages||16|
|Journal||Chinese Journal of Physics|
|Issue number||1 II|
|State||Published - Feb 1 2005|
ASJC Scopus subject areas
- Physics and Astronomy(all)