The influence of thick (∼10 nm) AlN overlayers on the interface structure and reactions in Si gate stacks with HfO 2 dielectrics was investigated. Annealing caused a reduction of the interfacial SiO 2 at the Si interface. At high temperatures (∼1000 °C) a silicide reaction was observed at the HfO 2/Si interface. No reactions were observed for stacks processed similarly but with WN or TiN overlayers instead of AlN. The reaction mechanisms, in particular, the role of oxygen deficiency of the HfO 2, and the consequences for the electrical properties are discussed.
Bibliographical noteFunding Information:
This research was supported by the SRC/SEMATECH Front End Processing Center. The authors thank Dr. Jiwei Lu and Sean Keane for the RTA and Dr. Steffen Schmidt for help with the TEM sample preparation. One of the authors (M.P.A.) would also like to acknowledge SRCEA/Intel for a fellowship.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)