Silicon on insulator-an emerging high-leverage technology

Silicon on insulator (SOI) has emerged as a high-leverage technology for a wide range of commercial and military applications. While the use of SOI is presently limited to special niche applications, such as radiation-hard space and defense electronics, thin-film SOI has become strategic for low-power, battery-operated portable systems and large-scale integrated logic and memory circuits with sub-half micron features. Substantial process simplification and cost reduction result from the dielectrically isolated structures. Other important SOI applications are the merger of several functions on the same die that performs reliably in adverse high-temperature environments. These include analog and logic functions, smart micromechanical sensors for automotive and distributed jet engine control with logic functions, or smart high-voltage CMOS logic/control elements. Manufacturable solutions to several material and device problems, however, must be demonstrated before SOI CMOS or BiCMOS designs enter the high-volume commercial manufacturing stage. Among these are the availability, cost, and quality of SOI material, gettering, electrostatic discharge protection, the floating-body problem in thin-film structures, and self-heating effects caused by the low thermal conductivity of the buried-oxide layer. The status of SOI material is discussed, including the different methods used to prepare large SOI wafers, wafer availability, cost reduction strategies, material characterization, and material quality. Applications and leverage areas are also described, with emphasis on problems and challenges that lie ahead for the large-scale manufacture of SOI products. The potential economic impact of SOI technology on the profitability of semiconductor manufacturing is described