EFFECT OF RAPID THERMALLY NITRIDED TITANIUM FILMS CONTACTING SILICIDED AND NONSILICIDED JUNCTIONS

The effect of rapid thermally nitrided titanium films contacting silic ided (titanium disilicided) and nonsilicided junctions has been studie d in the temperature range of 800 to 900-degrees-C. The rapid thermal nitridation of titanium films used as diffusion barriers between alumi num and silicon, has a major impact on shallow junction complementary metal oxide semiconductor technologies. During the process of rapid th ermal nitridation, the dopants in the junctions undergo a redistributi on and affect the electrical properties of shallow junction structures . This work focuses on using novel contact resistance structures to me asure the variation in electrical parameters for rapid thermally nitri ded titanium films annealed at different temperatures. The self-aligne d silicide (salicide)junctions in this study were formed using rapid t hermally annealed titanium films. Electrical contact resistance tester s were used to measure the interface contact resistance between the sa licide and silicon, as well as between the metal and the salicide. The results show that the interface contact resistance to the p- diffused salicided junctions increases with rapid thermal nitridation of the a dditional titanium film, whereas the interface contact resistance to t he n diffused salicided junction shows a decrease. Further, as a funct ion of the rapid thermal annealing temperature (for fixed titanium thi ckness), the nonsalicided diffusions show an increase in the interface contact resistance. The boron profiles at the TiSi2/Si interface obta ined using secondary ion mass spectroscopy show an excellent qualitati ve agreement with the electrical results for each of the conditions di scussed. The films were also characterized using Rutherford backscatte ring spectrometry and transmission electron microscopy and the results show good agreement with the measured variation in electrical paramet ers. These results also show that as the anneal temperature is increas ed, the TiN thickness increases, further the change in the silicide/si licon interface position with the nitridation of the additional titani um layer was verified.