Due to the less mismatched lattice and stable chemical and physical properties, sapphire(Al2O3) wafer is the popular substrates for III-V nitrides, superconductor and magnetic epi-film. They are widely used in GaN and thin-film epitaxial growth, silicon on sapphire, LED market and optics industry.
Silicon on sapphire (SOS) is a hetero-epitaxial process for metal-oxide-semiconductor (MOS) integrated circuit (IC) manufacturing that consists of a thin layer (typically thinner than 0.6 µm) of silicon grown on a sapphire (Al2O3) wafer. SOS is part of the silicon-on-insulator (SOI) family of CMOS (complementary MOS) technologies. Typically, high-purity artificially grown sapphire crystals are used.