AVS 53rd International Symposium
    Electronic Materials and Processing Friday Sessions
       Session EM+TF-FrM

Paper EM+TF-FrM1
Chemical Analyses and Electrical Studies of HfO@sub 2@/Y@sub 2@O@sub 3@, Y@sub 2@O@sub 3@/HFO@sub 2@ Bilayered and Y@sub x@Hf@sub y@O@sub z@ Intermixed Dielectric Materials for MIM Capacitors

Friday, November 17, 2006, 8:00 am, Room 2003

Session: High-k Dielectric & Multi-Functional Oxide Growth & Processing
Presenter: M. Kahn, LTM/CNRS, France
Authors: M. Kahn, LTM/CNRS, France
C. Vallee, LTM/CNRS, France
C. Dubourdieu, LTM/CNRS, France
M. Bonvalot, LTM/CNRS, France
J.R. Plaussu, LTM/CNRS, France
J. Ducote, LTM/CNRS, France
T. Baron, LTM/CNRS, France
O. Joubert, LTM/CNRS, France
Correspondent: Click to Email
Improving the capacitance density of MIM devices constitutes a real challenge to satisfy scaling rules for next IC generations and to reduce the cost as well. Silicon dioxide and nitride have been commonly used up to date as dielectrics in conventional MIM capacitors. However, they cannot provide capacitance values larger than 2fF/µm@super 2@. With further scaling going on at an active pace, high-@kappa@ dielectric materials offer a viable alternative to provide both high capacitance density and low leakage currents. This dielectric material of a MIM device has to meet several requirements such as a high capacitance density, low leakage currents and minimum variation of capacitance values with voltage bias. In a previous work, we studied TiN/Y@sub 2@O@sub 3@/Au capacitors and showed that Y@sub 2@O@sub 3@ exhibits appropriate electrical properties with low leakage currents and a capacitance density of 5 fF/µm@super 2@ @foonote 1@. However, we observed that the capacitance density cannot be further increased without a substantial increase in the leakage current, which in turn exceeds ITRS requirements. The aim of the present work is to overpass this capacitance limitation thanks to the introduction of a bilaminate dielectric material. Studies of MIM capacitors based on HfO@sub 2@/Y@sub 2@O@sub 3@, Y@sub 2@O@sub 3@/HFO@sub 2@ bilaminate and intermixed Y@sub x@Hf@sub y@O@sub z@ dielectric materials will be presented. These high @kappa@ dielectric layers are prepared by pulsed injection MOCVD on WSi@sub x@ bottom electrodes and the gold top electrode is realized by evaporation. The electrical behavior C(V) and I(V) of the obtained structures will be presented and discussed in terms of capacitance density, capacitance linearity and leakage currents. They will be correlated to chemical analysis results (XPS and SIMS), with special attention devoted to metal/oxide and oxide/oxide interface investigations. In particular, the observation of a non symmetrical C(V) curve will be highlighted with respect to the bilaminate stack HfO@sub 2@/Y@sub 2@O@sub 3@ and Y@sub 2@O@sub 3@/HFO@sub 2@ of dielectric materials. @FootnoteText@ @footnote1@ C. Durand, C. Vallee, C. Dubourdieu, M. Kahn, M. Derivaz, S. Blonkowski, D. Jalabert, P. Holliger, Q. Fang, I.W. Boyd ; J. Vac. Sci. Technol to be published (May/June 2006).