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Dielectric relaxation of high-k oxides.

Zhao C, Zhao CZ, Werner M, Taylor S, Chalker P - Nanoscale Res Lett (2013)

Bottom Line: Several mathematical models were discussed to describe the dielectric relaxation of high-k dielectrics.For the physical mechanism, dielectric relaxation was found to be related to the degree of polarization, which depended on the structure of the high-k material.The effect of grain size for the high-k materials' structure mainly originated from higher surface stress in smaller grain due to its higher concentration of grain boundary.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ, UK. cezhou.zhao@xjtlu.edu.cn.

ABSTRACT
Frequency dispersion of high-k dielectrics was observed and classified into two parts: extrinsic cause and intrinsic cause. Frequency dependence of dielectric constant (dielectric relaxation), that is the intrinsic frequency dispersion, could not be characterized before considering the effects of extrinsic frequency dispersion. Several mathematical models were discussed to describe the dielectric relaxation of high-k dielectrics. For the physical mechanism, dielectric relaxation was found to be related to the degree of polarization, which depended on the structure of the high-k material. It was attributed to the enhancement of the correlations among polar nanodomain. The effect of grain size for the high-k materials' structure mainly originated from higher surface stress in smaller grain due to its higher concentration of grain boundary.

No MeSH data available.


Related in: MedlinePlus

Frequency dependence ofkvalue extracted from C-fmeasurements in the MOS capacitors with high-kdielectrics [[52],[55],[56]].
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Figure 2: Frequency dependence ofkvalue extracted from C-fmeasurements in the MOS capacitors with high-kdielectrics [[52],[55],[56]].

Mentions: Frequency dispersion can now solely be associated with the frequency dependence of the k-value. The frequency dependence of the k value can be extracted as shown in Figure 2. The figure showed no frequency dependence of the k value in LaAlO3/SiO2, ZrO2/SiO2 and SiO2 stacks [56]. However, the frequency dependence of the k-value was observed in LaxZr1–xO2/SiO2 stacks [52]. The zirconium thin film with a lanthanum (La) concentration of x = 0.09 showed a sharp decreased k-value and suffered from a severe dielectric relaxation. A k value of 39 was obtained at 100 Hz, but this value was reduced to a k value of 19 at 1 MHz. The 10% Ce-doped hafnium thin film [55] also had a k value change from 33 at 100 Hz to 21 at 1 MHz. In order to interpret intrinsic frequency dispersion, many dielectric relaxation models were proposed in terms with frequency dependence of k value.


Dielectric relaxation of high-k oxides.

Zhao C, Zhao CZ, Werner M, Taylor S, Chalker P - Nanoscale Res Lett (2013)

Frequency dependence ofkvalue extracted from C-fmeasurements in the MOS capacitors with high-kdielectrics [[52],[55],[56]].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4228250&req=5

Figure 2: Frequency dependence ofkvalue extracted from C-fmeasurements in the MOS capacitors with high-kdielectrics [[52],[55],[56]].
Mentions: Frequency dispersion can now solely be associated with the frequency dependence of the k-value. The frequency dependence of the k value can be extracted as shown in Figure 2. The figure showed no frequency dependence of the k value in LaAlO3/SiO2, ZrO2/SiO2 and SiO2 stacks [56]. However, the frequency dependence of the k-value was observed in LaxZr1–xO2/SiO2 stacks [52]. The zirconium thin film with a lanthanum (La) concentration of x = 0.09 showed a sharp decreased k-value and suffered from a severe dielectric relaxation. A k value of 39 was obtained at 100 Hz, but this value was reduced to a k value of 19 at 1 MHz. The 10% Ce-doped hafnium thin film [55] also had a k value change from 33 at 100 Hz to 21 at 1 MHz. In order to interpret intrinsic frequency dispersion, many dielectric relaxation models were proposed in terms with frequency dependence of k value.

Bottom Line: Several mathematical models were discussed to describe the dielectric relaxation of high-k dielectrics.For the physical mechanism, dielectric relaxation was found to be related to the degree of polarization, which depended on the structure of the high-k material.The effect of grain size for the high-k materials' structure mainly originated from higher surface stress in smaller grain due to its higher concentration of grain boundary.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ, UK. cezhou.zhao@xjtlu.edu.cn.

ABSTRACT
Frequency dispersion of high-k dielectrics was observed and classified into two parts: extrinsic cause and intrinsic cause. Frequency dependence of dielectric constant (dielectric relaxation), that is the intrinsic frequency dispersion, could not be characterized before considering the effects of extrinsic frequency dispersion. Several mathematical models were discussed to describe the dielectric relaxation of high-k dielectrics. For the physical mechanism, dielectric relaxation was found to be related to the degree of polarization, which depended on the structure of the high-k material. It was attributed to the enhancement of the correlations among polar nanodomain. The effect of grain size for the high-k materials' structure mainly originated from higher surface stress in smaller grain due to its higher concentration of grain boundary.

No MeSH data available.


Related in: MedlinePlus