AVS 47th International Symposium
    Dielectrics Wednesday Sessions
       Session DI+EL+MS-WeA

Paper DI+EL+MS-WeA3
New High k Thin Films with Improved Physical and Electrical Properties

Wednesday, October 4, 2000, 2:40 pm, Room 312

Session: Alternate Gate Dielectrics
Presenter: Y. Kuo, Texas A&M University
Authors: Y. Kuo, Texas A&M University
J. Donnelly, Texas A&M University
J. Tewg, Texas A&M University
Correspondent: Click to Email
When the minimum device dimension is shrunk to 100 nm, the conventional silicon oxide cannot fulfill many requirements of the device.@footnote 1@ For example, the thin gate dielectric layer (e.g., < 1.2 nm) will have a high leakage current and cannot stop the boron penetration. The dielectric constant of silicon oxide (e.g., 4.0) is too low for the small-size storage capacitor cell. Therefore, it is urgent to develop a new kind of thin film dielectric that has a high dielectric constant (high k) and can satisfy all stringent material, process, and device requirements. Metal oxides are ideal candidates for the gate dielectric application because their compositions are simple and their k values are high enough to last for next several generations of devices. In addition to the high interface states, a metal oxide has the problem of high leakage current, which is caused by the polycrystalline phase formation during the high temperature process.@footnote 2,3@ In this paper, we present new results on high k metal oxides that have high amorphous-to-polycrystalline transition temperatures. By adding a third element into tantalum oxide, e.g., Ti, Cu, and Mo, the film can exist in the amorphous phase in an extended temperature range. The leakage current at a high temperature is lowered. Material and electrical characteristics of the new film, e.g., by x-ray diffraction, ellipsometer, current-voltage and capacity-voltage curves, will be shown and discussed. The influence of the deposition process, i.e., reactive co-sputtering, to film properties will also be presented. These new high k dielectrics have the potential of being used as gate dielectrics in future MOS devices. @FootnoteText@ @footnote 1@ International Technology Roadmap for Semiconductors, 1999 ed., SIA, etc. @footnote 2@ S. R. Jeon, S. W. Han, and J. W. Park, J. Appl. Phys. 77, 5978, 1995. @footnote 3@ R. B. van Dover, R. M. Fleming, L. F. Schneemeyer, G. B. Alers, and D. J. Werder, IEDM, 823, 1998.