Investigation of the electrical properties of the alkaline-earth oxides BaO, SrO and Ba_0.7Sr_0.3O on Si(001) as alternative gate dielectrics

authored by

A. Cosceev, D. Müller-Sajak, Herbert Pfnür, Karl Rüdiger Hofmann

Abstract

We present first investigations of the electrical characteristics of high-k amorphous BaO, SrO and crystalline Ba_0.7Sr_0.3O films on n-Si(001). The MOS structures were grown in a UHV chamber on structured SiO₂ samples with Si(001) windows and were capped with Au layers afterwards for ex-situ electrical characterization. The smallest capacitance equivalent oxide thicknesses (relative to SiO₂) achieved so far in BaO, SrO and Ba_0.7Sr_0.3O MOS-diodes were 1.0, 3.5 and 1.6 nm at oxide thicknesses of 5, 10 and 10 nm, respectively. The corresponding leakage current densities at + 1 V accumulation bias were 2.1, 1.3 · 10^{- 5} and 4.7 · 10^{- 6} A/cm². The lowest interface trap densities observed at ∼ 0.2 eV below the conduction band in MOS-diodes with BaO, SrO and Ba_0.7Sr_0.3O films were 5.2 · 10¹², 9.7 · 10¹¹ and 9.1 · 10¹⁰ eV^{- 1} cm^{- 2}, respectively. These results suggest that alkaline-earth oxides might be interesting materials for application as high-k gate dielectrics.

Organisation(s)

Institute of Solid State Physics
Institute of Electronic Materials and Devices

Type

Article

Journal

Thin Solid Films

Volume

518

Pages

S281-S284

ISSN

0040-6090

Publication date

22.10.2009

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials, Surfaces and Interfaces, Surfaces, Coatings and Films, Metals and Alloys, Materials Chemistry

Electronic version(s)

https://doi.org/10.1016/j.tsf.2009.10.108 (Access: Unknown)