Ultra shallow n/sup+//p junctions formed by out-diffusion from TiSi/sub 2/ with an amorphous silicon buffer layer

This paper presents a novel technology for ultra-shallow n/sup +/p junctions with low leakage current developed for the use of ULSI with scaled MOSFET's. The formation of shallow silicided junctions was investigated by implanting As into the TiSi/sub 2/ layer and the subsequent drive-in of the implanted arsenic into the Si substrate by a N/sub 2/ furnace. The TiSi/sub 2/ layer was formed by reaction of a deposited titanium with /spl alpha/ silicon. The junction quality is comparable to the conventional process (ITS). The major advantage of this process is more shallow junction depth than ITS's process. It is due to the depositied /spl alpha/-silicon film as a buffer layer that bulk-Si consumption during the silicidation process could be avoided.