Materials and Physical Properties of Novel High-k and Medium-k Gate Dielectrics

Rapid shrinking in device dimensions calls for replacement of SiO 2 by new gate insulators in future generations of MOSFETs. Among many desirable properties, potential candidates must have a higher dielectric constant, low leakage current, and thermal stability against reaction or diffusion to ensure sharp interfaces with both the substrate Si and the gate metal (or poly-Si). Extensive characterization of such materials in thin-film form is crucial not only for selection of the alternative gate dielectrics and processes, but also for development of appropriate metrology of the high-k films on Si. This paper will report recent results on structural and compositional properties of thin film SrTiO 3 and transition metal oxides (ZrO 2 and HfO 2 ).