For numerous applications in the microelectronics field, such layered structures with metallically conductive or semiconductive structures buried especially in silicon are becoming increasingly significant. For realizing such structures, for example of buried interconnects, heretofore there have been no suitable layered structures and processes of manufacture directed to them. A process is known in the state of the art in which the significant steps are lithographic structuring and etching of troughs in silicon, optionally selective deposition of a metal, the filling of the troughs with, for example, SiO.sub.2 and the removal of deposited materials can be mentioned.
This process is very expensive and, above all, is exceptionally problematical for submicron structuring magnitudes. Furthermore, in this process the danger of contamination of the metal/silicon boundary layer by undesired edge coverings is unavoidable. The production of epitactic layers is not possible therewith.
In the field of microelectronics, from "Silicides and Contacts for ULSI" in Handbook of Multilevel Metallization for Integrated Circuits, published by S. R. Wilson and C. J. Tracy, Noyes Publications, P. 32-96, 1993, two silicides, TiSi.sub.2 and CoSi.sub.2 have been described as state of the art, especially for the metallization of the source, gate and drain of metal oxide field effect transistors (MOSFET). Both suicides permit a self-adjusting process in the course of silicide formation and are characterized by a low electrical resistance of about 15 .mu.ohm cm. Flat p.sup.+ /n transitions with epitactic CoSi.sub.2 layers are advantageous in comparison to polycrystalline metallization. From Appl. Phys. Lett. 58, P. 1308-1310, 1991, it is known to produce monocrystalline CoSi.sub.2 layers with the so-called TiCo process by sputter deposition and heat treatment. Monocrystalline CoSi.sub.2 layers are characterized, by contrast with polycrystalline silicides by a significantly higher thermal stability: monocrystalline CoSi.sub.2 layers, especially as they are buried in silicon, are stable to about 1200.degree. C.
However, the hitherto known processes are precisely not suitable for the production of layered structures of the silicides since contamination and also a qualitatively insufficient passivation are problems which cannot be overcome.
USPTO Backgrounds
USPTO Backgrounds