Double SOI Structures and Device Applications with Heteroepitaxial Al2O3 and Si

Growth and properties of a double SOI (Si-on-insulator) structure, which consists of epitaxial Al2O3 as an insulator layer and epitaxial Si layers, are discussed. LP-CVD (low-pressure chemical vapor deposition) for γ- Al2 O3(100) growth on Si(100) substrates was combined with Si CVD through a sample exchanging chamber with reflection high-energy electron diffraction (RHEED) and quadrupole mass spectrometer (QMS) to grow successively and analyzed without exposure to air. These epitaxial multilayers were characterized by RHEED, Auger electron spectroscopy (AES), cross-sectional transmissin electron microscopy (TEM) and etching method. Metal-oxide-semiconductor (MOS) field effect transistor (FET) mobility was also studied on each Si layer. Both Si layers showed similar defect density and mobility. This double SOI structure was applied to fabrication of a pressure sensor for use at elevated temperatures up to 300° C.