A self-aligned silicide technology with the Mo/Ti bilayer system

Abstract

A self-aligned silicide technology using a bilayer of 60 nm Ti and 0.5 nm Mo deposited on blank and patterned silicon substrates was investigated. As a consequence of the direct formation of the C54 phase titanium silicide, a lower sheet resistance was always measured on narrow Si lines with the presence of the thin Mo interposing layer than without Mo, under otherwise the same conditions for silicidation. With Mo, the sheet resistance of the silicide formed on the patterned wafers was also much less sensitive to the Si linewidth. Moreover, the standard deviation in the sheet resistance across the wafer was found to be considerably smaller for the silicide formed with presence of Mo in comparison to reference sample. The presence of Mo at the TiSi interface only slightly increases the contact resistance between the silicide formed on the p + or n + silicon substrates. Thus, using the Mo/Ti bilayer to replace Ti appears to be very promising for sub-micron applications, as the deposition of Mo can easily be integrated into the standard process.