Heteroepitaxial Si/Al2O3/Si structures

A double-heteroepitaxial Si/γ-Al2O3/Si structure was realized. An epitaxial (100)Si layer with high quality was successfully grown on a (100)γ-Al2O3/(100)Si substrate by Si2H6 gas-source molecular beam epitaxy at substrate temperatures between 700 and 800 °C. The γ-Al2O3/Si substrate was fabricated by low-pressure chemical vapor deposition with Al(CH3 )3 and N2 O gases. The reflection high-energy electron diffraction patterns of the 3000-Å-thick Si epitaxial layer indicated streaked 2×1 patterns. This Si film had a mirror-like surface, and smooth surface morphology was observed from replica electron micrographs. From the Auger depth profile of the epitaxial layers, it was found that the double-heteroepitaxial Si/Al2O3/Si structure had a sharper interface between Al2 O3 and the epitaxial Si film due to the low growth temperatures.