AVS 50th International Symposium
    High-k Gate Dielectrics and Devices Topical Conference Monday Sessions
       Session DI-MoM

Paper DI-MoM11
Interface and Materials Properties of High-k Gate Stack Structures

Monday, November 3, 2003, 11:40 am, Room 317

Session: Electronic Properties of High-k Dielectrics and their Interfaces
Presenter: S. Sayan, Rutgers University
Authors: S. Sayan, Rutgers University
X. Zhao, Rutgers University
R.A. Bartynski, Rutgers University
T. Emge, Rutgers University
M. Croft, Rutgers University
T. Gustafsson, Rutgers University
D. Vanderbilt, Rutgers University
E.L. Garfunkel, Rutgers University
Correspondent: Click to Email
In this presentation, we describe recent results using soft x-ray photoemission (SXPS), inverse photoemission (IPE), and x-ray absorption spectroscopy (XAS) to examine HfO2 gate dielectrics and their interfaces with silicon and metal layers. In selecting an alternative (high-K) gate insulator, many parameters in addition to dielectric constant and thermal stability must be considered, including the barrier heights for tunneling. The SXPS and IPES results are used to determine the densities of states above and below the Fermi energy, in particular to elicit useful information on barrier heights. We find that interface dipoles affect the "effective workfunction" of metals via change in electrostatic potential as well as the band alignments, where the specific alignment depends on the interface properties. We have also performed first-principles density functional calculations to study the properties of the crystalline phases of HfO2 and ZrO2. The densities of valence and conduction bands are calculated and compared to experimental measurements. The thickness, layered structure, and crystal phase of the as-deposited and annealed films have been studied by XRD, XAS, MEIS, RBS and HRTEM. The authors would like to acknowledge useful interactions with colleagues at and NCSU (J.P. Maria, G. Parsons, G. Lucovsky and A. Kingon), J.Robertson (Cambridge University.UK), R. Tung (CUNY) and K.P. Cheung (ECE, Rutgers University) We also acknowledge the SRC for financial support.