AVS 46th International Symposium
    Electronic Materials and Processing Division Tuesday Sessions
       Session EM-TuA

Paper EM-TuA3
Investigation of Titanium Nitride Gates for Tantalum Pentoxide and Titanium Dioxide Dielectrics

Tuesday, October 26, 1999, 2:40 pm, Room 608

Session: High Dielectric Constant Materials and Thin Oxides
Presenter: D.C. Gilmer, Motorola
Authors: D.C. Gilmer, Motorola
C.C. Hobbs, Motorola
L. La, Motorola
B. Adetutu, Motorola
J. Conner, Motorola
M. Tiner, Motorola
L. Prabhu, Motorola
S. Bagchi, Motorola
P. Tobin, Motorola
Correspondent: Click to Email
The continuing push to decrease the feature size of microelectronic devices is hampered by some of the physical properties of the current materials. According to the National Technology Roadmap for Semiconductors (NTRS) projections, deep sub-micron device scaling indicates that silicon dioxide gate dielectrics must be scaled to less than 25 angstroms. It is generally accepted however, that such scaling will not be practical due to the rapid increase in tunneling current and resultant decrease in lifetime for these very thin silicon dioxide gate dielectrics. One alternative is to replace silicon dioxide with a material having a higher dielectric constant that will allow the use of thicker, less leaky, films. Towards this end, compounds such as tantalum pentoxide and titanium dioxide have been evaluated to replace silicon dioxide as a gate dielectric. Poly-silicon, currently used as the gate metal in MOSFETs, has been shown to react with transition metal oxides such as tantalum pentoxide and titanium dioxide to form an undesirable interfacial layer between the poly-silicon and metal oxide. Due to this incompatibility of poly-silicon metal gates with tantalum pentoxide or titanium dioxide gate dielectrics, an alternate metal gate material will need to be adopted for these alternative gate dielectrics. Titanium nitride (TiN), a mid-gap metal, has been extensively studied (and used) as a barrier material in many microelectronic devices. This paper reports on the investigation of physical vapor deposited and chemical vapor deposited titanium nitride for the application of a gate metal in capacitors (with sidewall spacers) using tantalum pentoxide or titanium dioxide as the gate dielectric. Electrical characteristics from C-V and I-V data, along with high resolution transmission electron microscopy of the TiN/gate oxide interface, for as-deposited and thermally annealed samples will be reported.