Silicon on sapphire
Silicon on sapphire (SOS) is a hetero-epitaxial process that consists of a thin layer of silicon grown on a sapphire (Al2O3) wafer. SOS is part of the Silicon on Insulator (SOI) family of CMOS technologies. SOS is primarily used in military and space applications because of its inherent resistance to radiation. SOS has seen little commercial use to date because of difficulties in fabricating the very small transistors used in modern high-density applications. This drawback is because the SOS process results in the formation of dislocations from crystal lattice disparities between the sapphire and silicon.
