Fabrication And Investigation Of Thicker SOI Films And SiGeOI Materials

With its unique structure, silicon-on-insulator (SOI) has been recognized as a promising materials for integrated circuits(ICs), where high speed and low power consumption are required .The SOI-based devices have been widely used in harsh environment, such as high temperature and radiation electronics in automotive, space and military application. Meanwhile, SOI may be used to fabricate the optical waveguide devices. In additional, the process of SOI is highly compatible with developed Si 1C technology. So SOI is a great potential material for optic-electronic integrated ciruits. Recently, SiGeOI has been studied by many researchers for its electronic and optical properties, including the properties of SiGe materials and SOI. However, it's difficult to prepare the SiGeOI with high Ge fraction in SiGe layer. In this work, the thicker SOI films applied to optical communication and SiGeOI with high Ge fraction were fabricated, then their properties were investigated.The thicker Si films were deposited onto SIMOX SOI substrates with standard oxygen dose of implantation by chemical vapor deposition. The thickness of epitaxial Si layer and buried oxide layer is uniform, and the crystal quality of epitaxial Si layer is good. The defects in the epitaxial Si layer resulted from the defects in the SOI substrate. The annealing at the proper temperature may decrease the resistivity of SOI substrate obviously and also improve the resistivity of epitaxial transitional layer partly. The surface roughness decreased obviously after epitaxial growth. The single rib waveguide was fabricated on the thick SOI, and the transmission loss is less than 0.4bB/cm at 1.55μm.The epitaxial Si layers on the SOI substrates with different oxygen dose of implantation were studied systematically. The defects in the epitaxial Si layer on low dosesubstrate are less than those in the epitaxial Si layer on standard dose substrate, and this mainly resulted from the different crystal quality of top $i layers on the different dose substrates. The better crystal epitaxial Si layer can be deposited on the lower dose substrate by reducing the implant oxygen dose in the substrate.The hydrogen annealing effects on epitaxial Si layer on standard dose SOI substrates were studied. The SOI surface may be improved by proper hydrogen annealing before epitaxial growth and the defects in the epitaxial Si layer decrease remarkably. It is good way to obtain epitaxial Si layer of good crystal quality on high dose SOI substrate with proper hydrogen annealing before epitaxial growth.The relaxed SiGeOI with high Ge fraction in SiGe layer was fabricated. The SiGe layers with 55% Ge fraction were deposited on the thinned and un-thinned SOI substrates with standard oxygen dose. After thermal oxidation, the SiGeOI with about 60% Ge fraction and relaxed degree above 90% was obtained on the thinned SOI substrate. And the SiGeOI with about 55% Ge fraction and relaxed degree above 90% was also obtained on the un-thinned SOI substrate. The distribution of Ge in SiGe layer is uniform. The thicker SiGe layer with low Ge fraction was deposited on the thinned SOI substrate. After long time thermal oxidation, the distribution of Ge in SiGe layer is gradient, and surface roughness of SiGe layer increased obviously, indicating it's difficult to obtain SiGeOI with high Ge fraction by oxidation of SiGe with low Ge fraction on SOI substrate.The effects of H ions of implantation into SiGe layer during thermal oxidation of SiGe/SOI were investigated. The implantation of H ions may delay the oxidation rate of SiGe layer and decrease the loss of Ge during oxidation, and H ions diffused out from SiGe layer after oxidation. The crystal quality of SiGe layer did not degrade because of the implantation of H ions after thermal oxidation.