IMPACT OF GE IMPLANTATION ON THE ELECTRICAL CHARACTERISTICS OF TISI2 P(+) N SHALLOW JUNCTIONS WITH AN ALPHA-SI (OR A POLY-SI) BUFFER LAYER/

A new technology for forming a titanium-silicide shallow junction by c ombining germanium implantation with an amorphous-silicon (or a poly-s ilicon) buffer layer has been proposed for MOSFET's, The use of a buff er layer between Ti and Si can avoid the consumption of bulk-silicon a nd the recession of TiSi2 film into the source/drain junctions during the silicidation process. In this study, the important role of germani um-implantation on the formation of TiSi2 contacted p(+)/n junctions w as examined, After subsequent implantation of Ge+ and B+ into the TiSi 2 film, samples were annealed at different temperatures to form p(+)/n junctions and C54-TiSi2. Since the penetration of titanium atoms was suppressed due to the germanium-implantation, the periphery leakage an d the generation leakage was improved and TiSi2/Si interfaces were eve n smooth. Therefore, p(+)/n junctions with a very low leakage current (0.192 nA/cm(2) at -5 V) and an excellent forward ideality factor (n a pproximate to 1.002) can be obtained. From the secondary ion mass spec trometry (SIMS) analysis, the junction depth is 400 Angstrom.