Entwicklung und Charakterisierung elektronischer Bauelementstrukturen auf der Basis einkristalliner CoSi$_{2}$/Si(100)-Heterostrukturen und sub-$\mu$m-Strukturierung dieses Schichtsystems durch lokale Oxidation

The fabrication process of a light emitting diode (LED)-array with porous silicon (PS) was investigated. The fundamental idea was to control the electroluminescence (EL) of a continuous PS-layer locally by an array ofvertical metal-semiconductor-feld-effect-transistors (MESFETs) based on single crystalline Si/CoSi$_{2}$/Si(100)-heterostructures. The LED-array consists of two crossed stripe-gratings buried in a silicon substrate with a continuous PS-layer on top. One grating acts as source-, the other one as gate- and the PS-layer as drain-electrode of the transistor. Secondary ion mass spectroscopy and channeling measurements have shown that highlyconducting source-gratings in intrinsic silicon substrate can be fabricated by implantation of phosphorous through a SiO$_{2}$-mask. The gate-grating was fabricated by implantation of cobalt ions through a mask perpendicular to the source-stripe-grating and subsequent annealing (ion beam synthesis, IBS). The current-voltage characteristic of the source and gate-electrode have proven the compatibility of phosphorous-implantation and IBS of CoSh. The compatibility of IBS with the electrolytic formation of porous silicon was demonstrated by the observed EL of porous silicon on buried CoSi$_{2}$-layers. In addition, a novel patterning method for single crystalline CoSi$_{2}$-layers on silicon based on local oxidation of the silicide was developed and optimized. The local oxidation of thin CoSi$_{2}$-layers was investigated in detail. A strong dependence of the patterning process on the silicide layer thickness as well as on the orientation of the oxidationmask was observed. The new process allows the patterning of 100 nm wide gaps between two metallic contacts by use of standard optical lithography