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Proceedings Paper

Flicker noise characteristics of MOSFETs with HfO2, HfAlOx, and Al2O3/HfO2 gate dielectrics
Author(s): Siva Prasad Devireddy; Bigang Min; Zeynep Celik-Butler; Fang Wang; Ania Zlotnicka; Hsing-Huang Tseng; Philip J. Tobin
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Paper Abstract

The flicker noise characteristics of MOSFETs with HfO2, HfAlOx, Al2O3 / HfO2 gate stacks have been studied, where both n and p type devices having 10 Å or 40 Å SiO2 interfacial layer (IFO) were considered. The corresponding equivalent oxide thickness (EOT) values were 23Å, 53Å for HfO2; 28.5Å, 58.5Å for HfAlOx; and 33Å, 63 Å for Al2O3 / HfO2. Gate leakage currents were (~ 2-5x10-5 A/cm2) which are 2 orders of magnitude lower compared to SiO2 devices with similar oxide thickness. The positive and negative threshold shifts as derived from the threshold voltages of n, p devices, respectively, suggested the presence of interface states between poly-gate and dielectric. Normalized power spectral density plot vs. gate overdrive shows that the devices with thin interfacial oxide (IFO) layer exhibit about an order of magnitude higher noise than those with thicker IFO owing to higher number of traps in the high-k and to the fact that carrier tunneling distance is ~20 Å. The Unified Model representing the carrier number and correlated mobility fluctuations was used to extract the oxide trap density and Coulomb scattering coefficient values. In general, n-type HfO2 devices yielded low noise, trap density and best mobility values compared to the other two gate stacks.

Paper Details

Date Published: 23 May 2005
PDF: 10 pages
Proc. SPIE 5844, Noise in Devices and Circuits III, (23 May 2005); doi: 10.1117/12.609500
Show Author Affiliations
Siva Prasad Devireddy, Univ. of Texas at Arlington (United States)
Bigang Min, Univ. of Texas at Arlington (United States)
Zeynep Celik-Butler, Univ. of Texas at Arlington (United States)
Fang Wang, Freescale Semiconductor Inc. (United States)
Ania Zlotnicka, Freescale Semiconductor Inc. (United States)
Hsing-Huang Tseng, Freescale Semiconductor Inc. (United States)
Philip J. Tobin, Freescale Semiconductor Inc. (United States)

Published in SPIE Proceedings Vol. 5844:
Noise in Devices and Circuits III
Alexander A. Balandin; Francois Danneville; M. Jamal Deen; Daniel M. Fleetwood, Editor(s)

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