Titanium nitride barrier formation and junction leakage characterization

Rapid thermal processing (RTP) of Titanium in an NH/sub 3/ ambient results in the formation of a bilayer TiN/sub x//TiSi/sub y/ diffusion barrier to aluminum spiking and junction leakage. Auger electron spectroscopy and Rutherford backscattering spectrometry were used to characterize the bilayer film properties as a function of starting titanium thickness, RTP temperature, metal deposition degas temperature and substrate doping. It has been demonstrated that barrier layers with incompletely reacted Ti have reduced performance; since unreacted Ti initiates the Al-Ti intermetallic formation, which leads to barrier failure. The optimization of the barrier parameters are discussed, with process guidelines for effective barrier formation.