Order and Disorder in Semiconductors

Abstract

The pervasive impetus of modern semiconductor technology has become an accepted fact. Scientific mastering of materials and processes has increased tremendously within a short time frame. Technological control has been derived from this scientific base. An industry with more than $100 billion worth of silicon devices per annum in 1994 as well as incredibly high growth rates of production and applications is an economic reality in addition to being a matter of international industrial policy. The materials aspect of using perfected single crystals and applying local doping control provides the basis of this unusual success. Earlier usage of materials differed remarkably. Bronze and steel are used for their specific bulk properties. Shaping and connecting pieces is at the heart of iron-age or bronze-age technologies. Integration inside a regular spatial array of a host crystal is the semiconductor principle. The “Royal Road” to modern microelectronics consists of initially procuring a perfected single-crystal host, then locally establishing electrical and optical properties inside the host by specific replacements of host atoms by foreign “dopants.” The somewhat disparaging expression of defect as a generic term for all deviations from the host perfection does not really convey the power of this “doping doctrine” for semiconducting materials. The early pioneers of germanium and silicon however, placed great emphasis on the experimental verification that n-type and p-type doping by elements of the adjacent columns in the periodic table were accompanied by changes in the lattice parameter with atomic substitution of the host atoms as the guiding principle.