AVS 52nd International Symposium
    Electronic Materials and Processing Monday Sessions
       Session EM-MoA

Paper EM-MoA9
The Effect of Nitrogen Incorporation on the Thermal Stability of La, Hf-aluminate Gate Stacks on Silicon

Monday, October 31, 2005, 4:40 pm, Room 309

Session: High-k Dielectric Growth and Processing
Presenter: P. Sivasubramani, University of Texas at Dallas
Authors: P. Sivasubramani, University of Texas at Dallas
P. Zhao, University of Texas at Dallas
F.S. Aguirre-Tostado, University of Texas at Dallas
J. Kim, University of Texas at Dallas
M.J. Kim, University of Texas at Dallas
B.E. Gnade, University of Texas at Dallas
R.M. Wallace, University of Texas at Dallas
Correspondent: Click to Email
The International Technology Roadmap for Semiconductors (ITRS) 2003 predicts the need for the introduction of high dielectric constant (k) gate dielectrics by 2006 to meet continued scaling requirements in metal-oxide silicon field-effect transistor (MOSFET) digital logic technology. Hf, Zr, group III or rare earth oxides with N, Al and/or Si additions have been identified as possible high-k gate dielectric candidates for near term MOSFET scaling.@footnote 1@ The thermal stability of a high-k dielectric film in direct contact with the underlying Si substrate is essential because out-diffusion of metal impurity atoms into the channel region during processing can cause carrier mobility degradation and affect the electrical performance of integrated circuit. Evaluation of the thermal stability of molecular beam deposited LaAlO@sub 3@ thin films show crystallization and out-diffusion of La and Al into Si (100) substrate when subjected to rigorous rapid thermal anneals (RTA) at or above 950 °C, 20 sec. in N@sub 2@ ambient.@footnote 2@ In this study, the effect of nitrogen incorporated into the La- and Hf-aluminate thin films and at the Si (100) interface will be discussed. Films are fabricated using reactive sputter deposition in Ar + N@sub 2@ followed by subsequent UV-O@sub 3@ oxidation at room temperature. High resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, x-ray reflectivity, x-ray diffraction, and secondary ion mass spectroscopy are utilized to characterize the gate stacks before and after RTA in the 850 to 1050 °C temperature range. This work is supported by the Semiconductor Research Corporation (SRC) FEP Transition Center. @FootnoteText@ @footnote 1@ITRS, Front End Processes, p. 33 [2003].@footnote 2@P. Sivasubramani, M. J. Kim, B. E. Gnade, R. M. Wallace, L. F. Edge, D. G. Schlom, H. S. Craft and J.-P. Maria, accepted for publication in Appl. Phys. Lett.