Anodization Of Zirconium For The Formation Of High-K Dielectric Zirconia (Zro2) Thin Film
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Date
2011-01
Authors
Zainal Abidin, Noor Rehan
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Publisher
Universiti Sains Malaysia
Abstract
Zirconia (ZrO2) is a promising material for future high-k gate dielectric applications. With the decreasing of the get dielectric thickness (<1.4nm), silicon dioxide (SiO2) layer suffered from basic problem of high tunneling leakage current due to its low dielectric constant (k=3.9). ZrO2 has a potential to overcome the tunneling leakage current problem since it has a high dielectric current (k=25) and good thermal stability on silicon (Si) substrate. The main objective of this work is to produce ZrO2 thin film with good properties and suitable for get dielectric application. ZrO2 thin film has been produced by anodizing zirconium (Zr) thin film sputtered on n-type Si substrate. Besides the thin film, anodization on Zr foil was also done as a comparison to the thin film. Anodization was done in alkaline solution of sodium hydroxide (NaOH). In this work, three mains parameters were studied; effects of different voltage, different concentration of solution and anodization time on the ZrO2 thin film. Compared to other parameters, voltage was found to give a significant impact on the properties of the formed ZrO2 thin film especially on the ZrO2 phases. ZrO2 phases transformed from tetragonal or cubic phase to monoclinic ZrO2 at high voltage. Thickness of the oxide formed was found to increase with voltage as measured using Filmetric. Electrical properties of the formed ZrO2 thin film show that the anodized samples became more insulated as the voltage increased with no breakdown voltage for samples anodized at 40 V and 50 V. This indicates that SiO2 forms at higher voltage. From this work, thin film that has been anodized at 20 V for 30 minutes in 1 M NaOH posses a good properties and suitable for get dielectric application. This show that ZrO2 thin film can be produced at room temperature using simple, easy and cheap techniques with comparable properties compared to other techniques.
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Zirconia (ZrO2) is a promising material for , future high-k gate dielectric applications