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Comparative study on in-situ surface cleaning effect of intrinsic oxide covering GaAs surface using TMA precursor and Al2O3 buffer layer for HfGdO gate dielectrics

Abstract

In this work, comparative study on cleaning effect of intrinsic oxide covering GaAs surface using TMA precursor and Al2O3 buffer layer were performed. GaAs substrates were either exposed to TMA precursor or deposited Al2O3 buffer layer under the same cycle prior to the deposition of HfGdO films. Combined X-ray photoemission spectroscopy (XPS) analysis and electrical evaluation, Trimethylaluminum (TMA) precursor can effectively remove surface oxides on GaAs substrate and inhibit oxygen diffusion as Al2O3 buffer layer does, and avoid the generation of low-k Al2O3 interface layer. Meanwhile the reduction of valence band offset as well as the raise of conduction band offset was obtained after passivated by atomic-layer-deposition (ALD) TMA precursor. The MOS capacitor with GaAs passivated by 20 cycles TMA presents almost no hysteresis, the minimum interface state density (~1.5×1012 cm-2eV-1), the greatest band offset (~2.86 eV), and the smaller oxide charge density (~-2.76×1013 cm-2), which leads to the maximum dielectric constant (~35.9) and the lowest leakage current density (~1.4×10-5 A•cm-2). Meanwhile, the leakage current density-voltage (J-V) characteristic curves at low temperature determined that the device has stable and reliable electrical properties.

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Publication details

The article was received on 05 Jan 2018, accepted on 12 Feb 2018 and first published on 13 Feb 2018


Article type: Paper
DOI: 10.1039/C8TC00070K
Citation: J. Mater. Chem. C, 2018, Accepted Manuscript
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    Comparative study on in-situ surface cleaning effect of intrinsic oxide covering GaAs surface using TMA precursor and Al2O3 buffer layer for HfGdO gate dielectrics

    J. Gao, G. He, S. liang, D. Wang and B. Yang, J. Mater. Chem. C, 2018, Accepted Manuscript , DOI: 10.1039/C8TC00070K

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