AbstractULSI packing density calls for sub-micron line widths, but on n-type polysilicon this can lead to incomplete titanium silicide C49 to C54 phase transformation after a conventional two step rapid thermal anneal (RTA). This study compares three different ion beam amorphization techniques: preamorphization, ion beam mixing and silicide amorphization, aiming at a complete phase transformation for submicron silicide lines. For preamorphization, an arsenic implantation at moderate energies (35–75 keV) was used to amorphize the top layer of the polysilicon prior to the titanium deposition. Ion beam mixing used a high-energy (200 keV) arsenic implantation after the titanium deposition to create an amorphous mix of silicon and titanium. These two methods did, each by themselves, lead to an increased fraction of C54 silicide grains already during the low temperature RTA, and a complete phase transformation during the subsequent high temperature RTA. Both methods lowered the thickness difference between titanium silicide on p- and n-type silicon. Silicide amorphization with 75 keV arsenic or 100 keV antimony, applied before the second RTA, did not significantly improve the silicide phase transformation.
Low‐temperature ion beam mixing of Pt and Si markers in Ge