A rapid thermal processing (RTP) method to improve the barrier properties of collimated titanium nitride (TiN) was studied. The RTP for the collimated TiN shows a significantly improved diffusion barrier property with reduced electrical contact resistance compared to a conventional furnace annealing process. Aluminum planarization was performed on subhalf micron contacts with various TiN barrier processes to examine electrical properties. When RTP is used, collimated TiN of much smaller thickness than the furnace-annealed collimated TiN shows reliable electrical contact properties without junction leakage failure at subhalf micron contacts. When simultaneous in situ RTP for Ti silicidation and stuffing is performed, we obtain greatly improved p(+) contact resistance. This is due to the phase transformation of Ti-Si amorphous layer to crystalline TiSi2 at Si/barrier interface, as observed by cross-sectional transmission electron microscope.