1/F noise performance of nMOSFETS with Hf-based gate dielectrics

Document Type

Conference Proceeding

Publication Date

12-1-2005

Abstract

The low frequency noise performance of n-channel MOSFETs with different Hf-based gate oxides, deposited by MOCVD and using polysilicon as a gate material has been investigated. Independent of the used gate oxide, the LF noise spectra of nMOSFETs are predominantly of the 1/f γ type, with the frequency exponent γ close to 1. The noise spectral density of HfO 2 devices are two orders of magnitude higher than for SiON and Hf xSi 1-xON, due to charge trapping in the oxide layer, while no significant differences are noticed among the various Hf xSi 1-xON compositions, where 0 < x < 100. The volume and the surface trap densities extracted from the noise are significantly higher for pure HfO 2 than for the Hf xSi 1-xON devices. In the latter case, trap densities are comparable with the ones extracted for SiON reference devices. The surface trap density calculated from N t varies from the highest for HfO 2 (∼3×10 13 cm -2) to ∼5×10 11 cm -2 for the Hf xSi 1-xON gate dielectrics, irrespective of the SiO 2/HfO 2 ratio x and has a comparable value for the SiON reference devices (∼8×10 11 cm -2). Hooge's parameter α H, as an alternative figure of merit, shows that the devices with MOCVD HfO 2 gate dielectric have the noisiest performance, while Hf xSi 1-xON devices yield the lowest an, even better than for SiON.

Identifier

31844454753 (Scopus)

Publication Title

Proceedings Electrochemical Society

First Page

151

Last Page

160

Volume

PV 2005-05

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