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Nitrogen (N2) Implantation to Suppress Growth of Interfacial Oxide in Mocvd Bst and Sputtered Bst Films

Published online by Cambridge University Press:  10 February 2011

Renee Nieh ,
Wen-Jie Qi ,
Yongjoo Jeon ,
Byoung Hun Lee ,
Aaron Lucas ,
Laegu Kang ,
Jack C. Lee ,
Mark Gardner  and
Mark Gilmer
Renee Nieh
Affiliation:
Microelectronics Research Center, University of Texas at Austin, Austin, TX 78758
Wen-Jie Qi
Affiliation:
Microelectronics Research Center, University of Texas at Austin, Austin, TX 78758
Yongjoo Jeon
Affiliation:
Microelectronics Research Center, University of Texas at Austin, Austin, TX 78758
Byoung Hun Lee
Affiliation:
Microelectronics Research Center, University of Texas at Austin, Austin, TX 78758
Aaron Lucas
Affiliation:
Microelectronics Research Center, University of Texas at Austin, Austin, TX 78758
Laegu Kang
Affiliation:
Microelectronics Research Center, University of Texas at Austin, Austin, TX 78758
Jack C. Lee
Affiliation:
Microelectronics Research Center, University of Texas at Austin, Austin, TX 78758
Mark Gardner
Affiliation:
Advanced Micro Devices, Austin, TX 78741
Mark Gilmer
Affiliation:
Advanced Micro Devices, Austin, TX 78741
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Abstract

Ba0.5Sr0.5TiO3 (BST) is one of the high-k candidates for replacing SiO2 as the gate dielectric in future generation devices. The biggest obstacle to scaling the equivalent oxide thickness (EOT) of BST is an interfacial layer, SixOy, which forms between BST and Si. Nitrogen (N2) implantation into the Si substrate has been proposed to reduce the growth of this interfacial layer. In this study, capacitors (Pt/BST/Si) were fabricated by depositing thin BST films (50Å) onto N2 implanted Si in order to evaluate the effects of implant dose and annealing conditions on EOT. It was found that N2 implantation reduced the EOT of RF magnetron sputtered and Metal Oxide Chemical Vapor Deposition (MOCVD) BST films by ∼20% and ∼33%, respectively. For sputtered BST, an implant dose of 1×1014cm−;2 provided sufficient nitrogen concentration without residual implant damage after annealing. X-ray photoelectron spectroscopy data confirmed that the reduction in EOT is due to a reduction in the interfacial layer growth. X-ray diffraction spectra revealed typical polycrystalline structure with (111) and (200) preferential orientations for both films. Leakage for these 50Å BST films is on the order of 10−8 to 10−5 A/cm2—lower than oxynitrides with comparable EOTs.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 567: Symposium R – Ultrathin SiO2 and Higg-K Materials for ULSI Gate Dielectrics , 1999 , 521
Copyright
Copyright © Materials Research Society 1999

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References

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