Material and electrical characterizations of high-k Ta2O5 dielectric material deposited on polycrystalline silicon and single crystalline substrate

• RTA annealing can mitigate bulk defects in Ta2O5 by repairing oxygen vacancies.
• Multiple electrical and material analyses on two types of substrates.
• The interface on top of a single crystalline substrate had fewer structural defects.
• The dielectrics on a single crystalline substrate possessed superior characteristics.

Samples of high-k Ta2O5 film as a high-k gate dielectric sputtered on both a single crystalline substrate and a polycrystalline silicon substrate and annealed at different temperatures were fabricated and compared. Samples were examined using various material and electrical analyses, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force spectroscopy (AFM), equivalent oxide thickness (EOT), JE characteristics, charge-to-breakdown Weibull plots, and gate voltage shift versus stress time. The research concludes that a Ta2O5 dielectric on a single crystalline substrate had fewer structural defects than a high-k/polysilicon interface, forming a dielectric with better material properties and electrical reliability.

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