Charge trapping and reliability characteristics of sputtered Y 2O3 high-k dielectrics on N- and S-passivated germanium

C. Mahata, M. K. Bera, T. Das, S. Mallik, M. K. Hota, B. Majhi, S. Verma, P. K. Bose, C. K. Maiti

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15 Scopus citations

Abstract

We demonstrate the potential of sulfur passivation to improve the interface characteristics between germanium (Ge) and Y2O3 high-k gate dielectric. Effects of nitrogen (N) and sulfur (S) passivation of the Ge surface on the charge trapping and reliability properties of Y2O 3/Ge gate stacks are studied in detail and the results are compared. Sulfur passivation of the Ge surface has been performed using both the wet sulfidation technique with aqueous ammonium sulfide and plasma sulfidation with H2S gas. N-passivation of Ge substrates has been performed in NO plasma for comparison. Ultrathin (∼15 nm) Y2O3 films are deposited on both the N- and S-passivated p-Ge (1 0 0) wafers. Y 2O3 films on the S-passivated Ge surface show low fixed oxide charge and interface state density than what is achieved with N-passivation. The electrical characterization results of MOS capacitors with Y2O3 films reveal the potential of S-passivation for the fabrication of Y2O3/Ge gate stacks for Ge MOSFETs.

Original languageEnglish
Article number085006
JournalSemiconductor Science and Technology
Volume24
Issue number8
DOIs
StatePublished - 2009

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