Abstract
The effects of UV-ozone treatment on ZnO thin films prepared by using radio-frequency magnetron sputtering are investigated. Decrease in the density of oxygen vacancy as well as increase in the density of oxygen interstitial were inferred from the UV-ozone treated samples. It was also found that a considerable difference in the work function (0.25 eV) is induced by UV-ozone treatment implying a shift in Fermi level. This shift was confirmed by capacitance-voltage measurements, which demonstrated that the boundary between the inversion region and the depletion region of a ZnO-based metal-oxide-semiconductor (MOS) capacitor positively shifts when UV ozone treated. Our results clearly indicate that the threshold voltage of a thin film transistor can be adjusted by modifying the ZnO surface via UV ozone treatment. MOS capacitors fabricated with UV-ozone treated HfO2and/or ZnO also yielded a smaller leakage current (~ 73%-90% smaller) and a larger breakdown voltage (~ 8%-11% larger). The physical mechanism behind the effect of the UV ozone treatment is addressed in this study with the help of X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy.
Original language | English |
---|---|
Pages (from-to) | 569-573 |
Number of pages | 5 |
Journal | Thin Solid Films |
Volume | 520 |
Issue number | 1 |
DOIs | |
Publication status | Published - 31 Oct 2011 |
Externally published | Yes |
Keywords
- Metal-oxide-semiconductor capacitor
- Thin films
- Threshold voltage
- UV-ozone treatment
- X-ray photoelectron spectroscopy
- Zinc oxide
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Metals and Alloys
- Materials Chemistry