Silicon on sapphire (SOS) is a hetero-epitaxial process for integrated circuit manufacturing 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 aerospace and military applications because of its inherent resistance to radiation. Typically, high-purity artifically grown sapphire crystals are used. The advantage of sapphire is that it is an excellent electrical insulator, preventing stray currents caused by radiation from spreading to nearby circuit elements. 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.

See Also

• Radiation hardened
• Silicon on Insulator