Effect of Ag doping on the performance of ZnO thin film transistor

Deuk Hee Lee, Ki Ho Park, Sangsig Kim, Sang Yeol Lee

    Research output: Contribution to journalArticlepeer-review

    22 Citations (Scopus)

    Abstract

    Ag-doped zinc oxide (SZO) thin film transistors (TFTs) have been fabricated using a back-gate structure on thermally oxidized and heavily doped p-Si (100) substrate. The SZO thin films were deposited via pulsed laser deposition (PLD) from a 1, 3, and 5 wt.% Ag-doped ZnO (1SZO, 3SZO, and 5SZO, respectively) target using a KrF excimer laser (λ, 248 nm) at oxygen pressure of 350 mTorr. The deposition carried out at both room-temperature (RT) and 200 °C. The SZO thin films had polycrystalline phase with preferred growth direction of (002) as well as a wurtzite hexagonal structure. Compare with ZnO thin films, the SZO thin films were characterized by confirming the shift of (002) peak to investigate the substitution of Ag dopants for Zn sites. The as-grown SZO TFTs deposited at RT and 200 °C showed insulator characteristics. However the SZO TFTs annealed at 500 °C showed good n-type TFT performance because Ag was diffused from Zn lattice site and bound themselves at the high temperature, and it caused generation of electron carriers. The post-annealed 5SZO TFT deposited at 500 °C exhibited a threshold voltage (Vth) of 11.5 V, a subthreshold swing (SS) of 2.59 V/decade, an acceptable mobility (μSAT) of 0.874 cm2/V s, and on-to-off current ratios (Ion/off) of 1.44 × 108.

    Original languageEnglish
    Pages (from-to)1160-1164
    Number of pages5
    JournalThin Solid Films
    Volume520
    Issue number3
    DOIs
    Publication statusPublished - 2011 Nov 30

    Bibliographical note

    Funding Information:
    This work is supported by the Core Competency project internally funded from Korea Institute of Science and Technology (KIST) , Republic of Korea.

    Copyright:
    Copyright 2011 Elsevier B.V., All rights reserved.

    Keywords

    • Ag-doped ZnO
    • Pulsed laser deposition
    • Thin film transistors
    • Zinc oxide

    ASJC Scopus subject areas

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

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