Materials, modern semiconductor doping

Once germanium is recovered and formed into blocks, it is further refined by the manufacturer of semiconductors. It is melted, and the small amounts of impurities such as arsenic, gallium, or antimony, are added. They act as either electron donors or acceptors that are infused (doped) into the mix. Then small amounts of the molten material are removed and used to grow crystals of germanium that are formed into semiconducting transistors on a germanium chip. The device can now carry variable amounts of electricity because it can act as both an insulator and a conductor of electrons, which is the basis of modern computers. 

Defects play an important part in both the chemical and physical behavior of solids and much of modern science and technology centers upon the exploitation or suppression of the properties that defects confer upon a solid. The chemical and physical aspects of a defect are intimately connected, but for simplicity, defects are often portrayed as influencing only chemical or physical properties. Thus, defects such as dislocations, which have a profound effect upon the mechanical properties of a solid, also influence chemical properties such as rates of dissolution and reaction, although these chemical aspects are not always mentioned. Similarly, defects that can be considered as more chemical in nature, such as impurity atoms, have profound effects on the physical properties of materials, as witnessed by doped semiconductors see Semiconductors, Semiconductor Interface. ... 

As expected, homogeneous semiconductor sensors in planar technology are characterized by much lower response time compared to sensors in the form of sinter pellets. Modern thin-film techniques allow precise doping of the material. 

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