Abstract
The NH3 plasma treatment on interfacial SiO2 has been proposed to reduce the interface dipole effect of HfO2/SiO 2 gate dielectric stacks. The X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectroscopy (UV-VIS) were used to establish the band diagram of the HfO2 films. The tetragonal crystallization phase of the HfO2 films examined by X-ray diffraction (XRD) was responsible for the band-gap increase during the NH3 plasma treatment. By using the Schottky emission and Fowler-Nordheim (F-N) tunneling, the effective electron barrier height of the Al/HfO2 gate stacks can be determined. Thus, the interface dipole and Fermi-level pinning induced flat-band voltage shifts of the Al/HfO2/SiO2/p-Si structure subjected to different NH3 plasma treatment conditions were obtained. It was found that the NH3 plasma treatment for about 4 min was sufficient for achieving the zero dipole interface of the HfO2/SiO2 gate dielectric stack due to the negligible movement of the oxygen ions between the HfO2 and the nitrided oxide.
Original language | English |
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Pages (from-to) | 120-122 |
Number of pages | 3 |
Journal | Microelectronic Engineering |
Volume | 109 |
DOIs | |
State | Published - 2013 |
Keywords
- Fermi-level pinning
- HfO
- High-k
- Interface dipole
- NH plasma