The electrical, metallurgical, and mechanical behavior of the Ti films heat-treated in a rapid thermal processor in NH3 and N2 ambient in the temperature range of 550 to 750-degrees-C were studied. In addition, formation of the TiN film by rapid thermal nitridation (RTN) in NH3 ambient and its barrier integrity were also studied as a function of the nitridation temperature and duration. n+ and p+-type silicon and thermal oxide were used as substrates. Electron spectroscopy for chemical analysis, Rutherford backscattering spectroscopy, and sputtered neutral mass spectrometry were used to study the extent of the interactions between N, Ti, and Si as well as identification of the TiN phase and its thickness. The thermal stability of the TiN film as a diffusion barrier was investigated in the temperature range of 400 to 475-degrees-C. The diffusion barrier integrity of the TiN film and its thermal stability were investigated via substrate junction leakage current and contact resistance measurements done on test structures fabricated using a complete 1.0 and 0.85 mum complimentary metal oxide semiconductor erasible programmable read-only memory mask sets. Presented data shows that the decrease in the sheet resistance and the increase in the stress of the heat-treated Ti films as the temperature increases are due to the presence of silicon in the Ti films. Similar results were obtained when heat-treatment was carried out in N2 ambient. The analytical analyses indicate that the thickest TiN film which can be formed by the RTN process in NH3 ambient, in the temperature range of 590 to 750-degrees-C, is only 200 to 240 angstrom and is formed at about 600 to 610-degrees-C. The substrate junction leakage current data taken from the test structures indicate that the TiN film formed by one-step nitridation in NH3 ambient is not electrically and thermally reliable as a diffusion barrier for fabrication of the integrated circuit devices with shallow junctions (less-than-or-equal-to 0.2 mum) regardless of the nitridation temperature and duration, and as-deposited thickness of the Ti film. This short-coming is attributed to an inadequate thickness of the TiN film and the formation of (Ti-Si-Al) ternary solution. Finally, to overcome this problem, a multistep nitridation process was developed that produced the thickest TiN film at the contacts and on the oxide layer (borophosphosilicate glass/borophosphosilicate tetraethyl orthosilicate), as well as a TiSi2 layer under the TiN film at the contacts. The diffusion integrity of this TiN/TiSi, bilayer was also evaluated via substrate junction leakage current and contact resistance measurements. The results indicate the suitability of this film as a diffusion barrier for submicron integrated circuit devices having shallow junctions. Furthermore, these results indicate that the presence of the TiN layer at the contacts is essential if the TiN film formed by RTN process in NH3 ambient is to be used as a diffusion barrier.