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THE element silicon (Si) has attained a dominant position in the field of manufacturing micro‐electronic components. This dominant position is due to properties which will perhaps assume even greater significance in the future. Silicon is universally applicable both for sensors, and for analogue and logic circuits as well as for memory cells. It is comparatively easy to work with. It is completely non‐toxic, and is therefore environmentally harmless. Supplies of silicon are almost limitless; after oxygen silicon is the second most common element in the earth's crust. Silicon crystallises in a diamond lattice (Fig. 1). Its universal applicability as a semiconductor is not synonymous with the optimal suitability for the current special application. The most far‐reaching proposal for overcoming the inadequacies of natural semiconductors came from L. Esaki. A superlattice structure (Fig. 2) is produced by arranging alternate layers of different elements. The atoms A and B are arranged periodically with a period length which superposes the natural period of the lattice. If the period of the superlattice is small (e.g. 3 to 100 atomic layers) new properties would be expected, which arise from the mixed crystals (synthetic semiconductor). The properties of the synthetic semiconductor are controllable by the geometrical dimensions and the concentrations of the superlattice structure.