Multi-chamber electron beam evaporator system with targeted gas supply for the production of electrical contacts and thin functional layers

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The fabrication of devices based on III-V semiconductor materials requires the electrical contacting of n- and p-doped regions. In order to avoid electrical losses and to allow the functioning of the components electrical contacts with ohmic characteristics are necessary. These consist of layer sequences of electrically active metals, adhesion promoters and very good electrical conductors. For n-doped arsenides, the sequence Ni / Au / Ge, for p-doped Ge / Pd, for n-doped nitrides, e.g. Ti / Al / {Pt, Ti, Ni, Mo} / Au, required for p-doped nitrides Ni / Au and for n-doped phosphides Ge / Au. The first material is used as a doping material and is protected by the following layers or increased by this the adhesion or electrical conductivity. So that the individual layers are not oxidized or contaminated and thus lose their properties, it is necessary that the layer sequence is deposited under UHV conditions. For this purpose, a UHV multi-chamber system with lock is necessary in which the individual materials are vaporized depending on their melting point and vapor pressure by means of electron beam arrangement. By expanding the plant to include other materials such as Cs, Ge and Si, as well as the possibility of targeted gas supply, the range of application of the plant can be greatly expanded and thus serve other purposes, such as. Production of negative electron affinity surfaces for photocathodes, thin oxide films for antireflection films, or thin epitaxial films based on thin Ge or Si.