Impact of Deep Ultraviolet-Ozone Photoactivation on Dielectric Properties of Amorphous SrTiO₃ Thin Films

Abstract:

Strontium titanate SrTiO₃ thin films have been fabricated by radio frequency magnetron sputtering on P-type Si at substrate temperature of 200°C. Two different postdeposition annealing methods were applied on the sputtered films. Specifically, conventional thermal annealing at 300°C for 60 min and photoactivation treatment under deep ultraviolet-ozone for 30 min. The dielectric properties of the SrTiO₃ thin films were investigated by fabricating Au/STO/p-Si MOS capacitors. A dielectric constant (κ) with a value of 13 was obtained for as-deposited film, which has a thickness of 107 nm. While post-annealed samples showed elevated values of κ, precisely, 15.33 and 19.32 for films exposed to deep ultraviolet-ozone photoactivation and films annealed at 300°C, respectively. All devices showed a leakage current in the order of 10^-8 A/cm² at 1V. Based on XPS analysis, photo-activated films revealed the lowest percentage of oxygen vacancies, which designates the capability of this technique to enhancing films quality at a lower temperature.

• Periodical: Key Engineering Materials (Volume 907)
• Pages: 17-23
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.907.17
• Online since: January 2022
• Authors: Asmaa Mudhaffar, Hala Al-Jawhari*
• Keywords: High-K Dielectric, Radio-Frequency Sputtering, Strontium Titanate, Ultraviolet-Ozone Photoactivation

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