| AVS 55th International Symposium & Exhibition | |
| Thin Film | Tuesday Sessions |
| Session TF-TuA |
| Session: | Applications of ALD II |
| Presenter: | H. Li, Rohm and Haas Electronic Materials |
| Authors: | H. Li, Rohm and Haas Electronic Materials D.V. Shenai, Rohm and Haas Electronic Materials R.G. Gordon, Harvard University |
| Correspondent: | Click to Email |
The study of ultrathin gate dielectrics has recently gained great attention due to the technological need to replace SiO2 films in the metal-oxide-semiconductor field-effect transistors (MOSFETs).1 According to the International Technology Roadmap for Semiconductors (ITRS),2 the implementation of high-k gate dielectrics with a dielectric constant between 10 and 20 will be produced by leading manufacturers by 2008 in order to meet both low leakage current density and performance requirements. Ternary rare earth oxides are emerging as promising candidates for these applications. As shown in earlier report,3 lanthanum lutetium oxide films (LaLuO3) obtained by pulsed laser deposition (PLD) technique showed a high dielectric constant of 32, very low leakage current density, remaining amorphous up to 1000 ºC and excellent performance. Similarly atomic layer deposition (ALD) of ternary rare earth oxide films such as GdScO3 or LaScO3 also demonstrated the potential for substituting current high k material.4 However Lu and Sc elements are much less abundant in earth compared to other rare earth elements. So the precursors based on Lu or Sc can be extremely expensive to manufacture. Finding less expensive metals while maintaining those unique properties is urgent. Y, Yb and Er are three rare earth elements which are similar to Lu and Sc in ionic radii, but are much less inexpensive because of their natural abundance. In this presentation, we report the Y, Yb and Er precursors based on formamidinate platform, which has been demonstrated to offer higher vapor pressure and higher thermal stability of the sources than commercially available conventional precursors.5 We will also report the ALD growth using H2O and O3 as co-reactants within the acceptable window of deposition temperatures. The resultant films will be characterized by AFM, XRD, and TEM.
1Wilk et al, J. Appl. Phys. 2001, 89, 5243.
2International Technology Roadmap for Semiconductors: 2007 edition.
3(a) Lopes et al, Appl. Phys. Letts. 2006, 89, 222902.
4(a) Kim et al, App. Phys. Letts. 2006, 89(13), 133512/1-133512/3. (b) Wang et al, AVS 55th International Symposium, Boston, MA, 2008.
5Li et al, 8th International Conference on Atomic Layer Deposition, Bruges, Belgium, 2008.