Study of Sitox Process and its Application to Advanced MOS Devices

Abstract

ABSTRACTIn this study, the application of Sllicidation Through OXide (SITOX) process to TiSi2 formation is extensively investigated. The data show that the decomposition of an interfacial SiO2 layer between Ti and the Si substrate depends not only on its thickness but also on the silicidation temperature and the type of dopants in the Si substrate. In general, high annealing temperatures and B-doped p+ Si substrates enhance the decomposition of interfacial SiO2. After the silicidation process, the O concentration at the TiSi2/Si interface is approximately two orders of magnitude higher with SITOX than with the conventional silicidation process. This high interfacial O concentration has no significant effect on the electrical properties of SITOX TiSi2 films and junction diodes. The X-ray Diffraction analysis shows that SITOX TiSi2 films have a polycrystalline structure as do conventional TiSi2 films. The average grain size in a 100 nm SITOX TiSi2 film is estimated to be about 10 μm wide, while that in a 120 nm conventional TiSi2 film is about 3 μm. Histograms of leakage current for junction diodes confirm that the SITOX process can improve the uniformity of leakage currents.