Computers are increasingly miniaturized, while their performance is increased. This is achieved by a fabrication technology that applies many billions of electronic components to semiconductor chips of a few square millimeters only with highest precision.Fabrication of these chips is mainly based on monocrystalline silicon platelets of a few millimeters in thickness, so-called wafers. By doping certain areas of the silicon substrate with impurity atoms, such as phosphorus, semiconducting transistors and other electronic components are produced.For doping, a layer of phosphorus-containing organic molecules is often applied to the wafer. To dope selected areas only, the organic layer is structured by etching. To prevent evaporation, an inorganic layer has to be applied to the organic one. By short heating, phosphorus atoms diffuse from the organic layer into silicon and the inorganic layer can be removed again. This technology known as Monolayer Doping (MLD), however, has the disadvantage that the number of atoms available for doping is limited.KIT scientists of the Institute of Functional Interfaces (IFG) have now developed a method that uses a single, purely inorganic layer for doping only. This technology referred to as Mineral Interface Doping (MID) is based on immersion of the cleaned wafer into various solutions. Depending on the length of immersion, mineral coatings of 20 to 200 nm in thickness are formed on the silicon. Structuration is then accomplished by etching again. Doping atoms diffuse into these structures by short heating.The new technology allows for high doping densities and the construction of even smaller semiconductor components. The process is being applied for doping with phosphorus and arsenic at the moment. Organic materials are not needed. As a result, there is no risk of contaminating the semiconductor by carbon atoms. As no additional protection layer has to be applied, costs can be saved by a simplified production process.