| 摘要 |
<p>Device quality, single crystal film of cubic zinc-blende aluminum nitride (AlN) is deposited on a cubic substrate, such as a silicon (100) wafer by plasma source molecular beam epitaxy (PSMBE). The metastable zinc-blende form of AlN is deposited on the substrate at a low temperature by a low energy plasma beam of high-energy activated aluminum ions and nitrogen ion species produced in a molecular beam epitaxy system by applying a pulsed d.c. power to a hollow cathode source. In this manner, films having a thickness of at least 800 Å were produced. The lattice parameter of as-deposited films was calculated to be approximately 4.373 Å which corresponds closely to the theoretical calculation (4.38 Å) for cubic zinc-blende AlN. An interfacial layer of silicon carbide, specifically the cubic 3C-SiC polytype, interposed between the epitaxial film of zinc-blende AlN and the Si(100) wafer provides a template for growth and a good lattice match. The epitaxial layer of zinc-blende AlN has been characterized for its physical and optical properties. As a result, experimental data confirmed that zinc-blende AlN is an indirect semiconductor and has a bandgap about 5.34 eV. Due to the extraordinary piezoelectric properties of zinc-blende AlN, an illustrative device embodiment is a surface acoustic wave (SAW) device comprising interdigitated electrodes deposited by conventional means on the surface of the epitaxial layer of zinc-blende AlN to convert an electrical signal to a surface acoustic wave and vice versa.</p> |
