IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Dielectrics Tuesday Sessions
       Session DI-TuM

Paper DI-TuM8
Correlations Between Local Bonding and Electronic Structure, and Gate Dielectric Performance of Zirconium Silicate Alloys

Tuesday, October 30, 2001, 10:40 am, Room 130

Session: High K Dielectrics II
Presenter: G. Rayner, Jr., North Carolina State University
Authors: G. Rayner, Jr., North Carolina State University
D. Kang, North Carolina State University
M. Schultz, North Carolina State University
G. Appel, North Carolina State University
G. Lucovsky, North Carolina State University
H. Ade, North Carolina State University
D.E. Aspnes, North Carolina State University
D.E. Sayers, North Carolina State University
Correspondent: Click to Email
Zirconium silicate alloys have been prepared by remote plasma enhanced metal organic chemical vapor deposition, RPE-MOCVD, using down-stream injected SiH@sub 4@ as the Si-atom source, Zr(IV) t-butoxide as the Zr-atom source, and plasma excited O@sub 2@/He mixtures to produce active oxygen species to drive the deposition reactions. Bulk film properties have been studied for as-deposited films, and films subjected to post-deposition annealing at temperatures to 1000C in an Ar ambient. This paper extends previously reported studies of thermal stability (chemical phase separation and crystallization) by infrared, IR, spectroscopy and x-ray diffraction, XRD.@footnote 1@ Specific spectroscopic studies include i) x-ray photoelectron spectroscopy, XPS, ii) x-ray absorption spectroscopy, XAS, iii) extended x-ray absorption fine structure, EXAFS, and iv) spectroscopic ellipsometry, SE. The spectroscopic studies have confirmed that the lowest lying anti-bonding states are derived from d-states of the Zr-atoms. Results demonstrate that the energy of these states relative to vacuum, and the Si conduction band, do not change as a function of alloying, or as a function of long or short range order. This result is consistent with a molecular orbital description of the electronic structure derived from the Zr d-states. This aspect of the electronic structure has important implications for the interpretation of electrical studies, e.g., current-voltage and capacitance-voltage measurements that are also reported in this talk. For example, changes in the coordination and bonding symmetry of the bonding and anti-bonding orbitals derived from Zr d-states provide insights into the microscopic mechanism responsible for enhancements in the dielectric constant at low ZrO@sub 2@ concentrations.@footnote 2@ Supported by ONR, SRC and the Sematech SRC Center for Front End Processes @FootnoteText@ @footnote 1@ G. Rayner, R. Therrien and G. Lucovsky, MRS Symp Proc 611, c1 3.1 (2001) @footnote 2@ G. Lucovsky and G. Rayner, Appl. Phys. Lett. 77, 2912 (2000).