Silicon on sapphire (SOS, English, German: , silicon on sapphire ') referred to in the semiconductor technology, a special design for semiconductor devices of silicon on the insulating substrate made ​​of sapphire.

SOS is part of the silicon-on -insulator family (SOI, dt » silicon on insulator ").

Integrated circuits (ICs) are manufactured in a heteroepitaxial process in which a thin layer of single crystal silicon on a sapphire wafer is prepared. The sapphire wafers are cut from high-purity, single-crystal sapphire artificially farmed. The advantages of sapphire are its good electrical insulation, which ionizing radiation interspersed voltages prevents act on adjacent circuit elements, as well as its approximately matching the lattice constant and the high thermal conductivity.

SOS allows the production of transistors and ICs with very high operating voltage or very high radiation resistance used (for example, for use on board satellites in the field of the Van Allen belts ) and are primarily in the aeronautical and military applications. The microprocessor RCA1802 is a well known example of a manufactured at the SOS method semiconductor.

SOS was commercially at least until 2006 little used because it is very difficult to produce extremely small transistors. However, these are needed for highly integrated components. The difficulty is caused by dislocations that arise between the silicon and sapphire due to the disparity of the crystal lattice.