High-k gate dielectrics for scaled CMOS technology

Abstract

This paper summarizes our results on several high-k gate dielectrics, including TiO/sub 2/, Ta/sub 2/O/sub 5/, ZrO/sub 2/, HfO/sub 2/, and Al-doped varieties of the above. Among them, TiO/sub 2/ and Ta/sub 2/O/sub 5/ have higher dielectric constants than others, while ZrO/sub 2/ and HfO/sub 2/ are thermodynamically more stable against the formation of SiO/sub 2/ 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.