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

Paper DI-MoA6
Optical Properties of Prospective High-k Dielectric Films

Monday, November 15, 2004, 3:40 pm, Room 304B

Session: High-k Dielectrics: Electronic Properties
Presenter: E. Cicerrella, OGI School of Science & Engineering of OHSU
Authors: E. Cicerrella, OGI School of Science & Engineering of OHSU
J.L. Freeouf, OGI School of Science & Engineering of OHSU
L.F. Edge, The Pennsylvania State University
D.G. Schlom, The Pennsylvania State University
T. Heeg, Inst. fur Schicht und Ionentech., Germany
J. Schubert, Inst. fur Schicht und Ionentech., Germany
S.A. Chambers, Pacific Northwest National Laboratory
Correspondent: Click to Email
The current gate dielectrics in silicon MOSFETs are unable to prevent excessive gate leakage as devices continue to shrink. The effort continues to establish appropriate materials to replace SiO2 to remove this problem. New processing issues arise as we deal with these new materials â?" especially as they are deposited on Si substrates. We have established that some rare earth perovskites have high dielectric constants. We believe that they will be thermodynamically stable with silicon and therefore are possible gate dielectrics. We discuss thin films of one candidate material, LaScO3, which were grown by molecular beam deposition on Si substrates and pulsed laser deposition on MgO substrates. Using spectroscopic ellipsometry in the Far UV (5 eV - 9 eV) and the UV/VIS (1.5 eV - 5 eV), as well as transmission studies between 1.5 eV and 6 eV, we have established that low temperature deposition leads to a reduced band gap and a lower density as compared with the bulk crystal. We seek to understand the impact of deposition technologies as well as other process steps, such as high temperature anneals. To this end we have had high temperature anneals performed on these films and then repeated these measurements and analysis. In this analysis we shall seek changes in density, band gap, refractive index, and interfacial layers between the substrate and the deposited film.