Impact of point defects on III-nitride tunnel devices.

ORAL

Abstract

Heterostructures using GaN and InGaN are being pursued in designs of tunnel field-effect-transistors (TFETs) to enable low-power switching devices. Point defects and impurities in these heterostructures can adversely affect the performance of these devices through Shockley-Read-Hall (SRH) and Trap-Assisted-Tunneling (TAT) processes. Using first-principles calculations based on a hybrid functional, we calculate the thermodynamic and charge-state switching levels as well as nonradiative recombination rates of point defects and impurities in GaN and InGaN. Gallium vacancies and their complexes, in particular, are found to be potentially detrimental centers. We then investigate how these defects can contribute to SRH and TAT processes in a nitride TFET device.

*This work was supported by the Center for Low Energy Systems Technology (LEAST), one of the six SRC STARnet Centers, sponsored by MARCO and DARPA.

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Authors

  • Darshana Wickramaratne

    • Materials Department, UC Santa Barbara

  • John L. Lyons

    • Center for Functional Nanomaterials, Brookhaven National Laboratory
    • University of California Santa Barbara

  • Chris G. Van de Walle

    • University of California, Santa Barbara
    • Univ of California - Santa Barbara
    • Materials Department, University of California, Santa Barbara
    • Materials Department, UC Santa Barbara
    • UCSB
    • University of California Santa Barbara