Evolution and Future Trends of SIMOX Material

Abstract

Oxygen-implanted silicon-on-insulator (SOI) material, or SIMOX (separation by implantation of oxygen), is another chapter in the continuing development of new material technologies for use by the semiconductor industry. Building integrated circuits (ICs) in a thin layer of crystalline silicon on a layer of silicon oxide on a silicon substrate has benefits for radiationhard, high-temperature, high-speed, low-voltage, and low-power operation, and for future device designs. Historically the first interest in SIMOX was for radiation-hard electronics for space, but the major application of interest currently is low-power, high-speed, portable electronics. Silicon-on-insulator also avoids the disadvantage of a completely different substrate such as sapphire or gallium arsenide. Formation of a buried-oxide (BOX) layer by high-energy, high-dose, oxygen ion implantation has the advantage that the ion-implant dose can be made extremely precise and extremely uniform. However the silicon and oxide layers are highly damaged after the implant, so high-temperature annealing sequences are required to restore devicequality material. In fact SIMOX process development necessitated the development of new technologies for high-dose implantation and high-temperature annealing.