High-k gate dielectrics for scaled CMOS technology

This paper summarizes our results on several high-k gate dielectrics, including TiO2, Ta2O5, ZrO2, HfO2, and Al-doped varieties of the above. Among them, TiO2 and Ta2O5 have higher dielectric constants than others, while ZrO2 and HfO2 are thermodynamically more stable against the formation of SiO2 on Si, and the addition of Al raises the temperature for crystallization for all of them. Both MOS capacitors and MOSFET's have been fabricated with these high-k gate dielectrics, and their properties have been studied. We have also utilized the temperature-dependent IN characteristics of these high-k dielectrics to study their current conduction mechanisms and to construct their energy band diagrams.