AVS 51st International Symposium
    Electronic Materials and Processing Monday Sessions
       Session DI-MoA

Paper DI-MoA9
Interface Band Alignment in High-k Gate Stacks

Monday, November 15, 2004, 4:40 pm, Room 304B

Session: High-k Dielectrics: Electronic Properties
Presenter: P. Hartlieb, Rutgers University
Authors: P. Hartlieb, Rutgers University
E. Bersch, Rutgers University
S. Sayan, National Institute of Standards and Technology
R. Bartynski, Rutgers University
E. Garfunkel, Rutgers University
Correspondent: Click to Email
Understanding and controlling band alignment remains a key aspect that must be realized if novel materials are to be incorporated in future nano-electronic devices. Photoemission, inverse photoemission, internal photoemission, and complementary methods have been used to examine (i) amorphous high-K gate dielectrics and their interface on Si, (ii) metal-oxide interfaces, and (iii) multilayered gate stacks that include metal gates and high-K dielectrics. Materials changes occur at the various interfaces during growth and processing that strongly effect device properties including the band alignment. The potential changes (effective work function) across the films have been examined as a function of material, thickness and processing ambient. Experimental results are compared to theoretical calculations to better understand the electronic properties of the different crystalline structures. It is found that the band gap, barrier height and dielectric response of this class of materials are very phase-dependent. Inverse photoemission measurements show that the conduction band shifts to higher energy going from HfO@sub 2@ to HfSiO with increasing SiO content. In contrast, addition of nitrogen shifts the conduction band to lower energy. The conduction band edge of HfO@sub 2@ rapidly shifts to lower energy upon Al metallization @footnote 1@. @FootnoteText@ @footnote 1@ The SRC, iSematech, and NSF are gratefully acknowledged for their financial support.