Invited) Tuning Dielectric Properties of Epitaxial Lanthanide Oxides on Silicon
Invited) Tuning Dielectric Properties of Epitaxial Lanthanide Oxides on Silicon
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特邀）调整硅上外延镧系氧化物的介电性能
DOI：
10.1149/06102.0003ecst
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
M. Eizenberg
中科院分区：
文献类型：
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作者：
H.J. Osten;D. Schwendt;A.R. Chaudhuri;A. Fissel;P. Shekhter;M. Eizenberg
生长在硅上的薄晶体氧化物的介电性能对结构和对称性的微小变化很敏感。在这里，我们报告了应变诱导对介电性能影响的不同研究。首先，我们报道了在Si(111)衬底上外延Gd2O_3的介电常数与层厚度的关系。K值随层厚的增加而急剧下降，在8 nm左右达到体积值。控制(Gd1-xNdx)_2O_3三元薄膜中的氧化物组分使我们能够调节晶格与硅的失配，从而调节介电常数的应变引起的变化。我们发现，仅仅是立方晶格的四方形变不足以解释K值的巨大提高；发生了更严重的应变引起的结构相变。此外，外延氧化物薄膜的介电性能已经被发现通过掺入合适的掺杂剂而显著改善。我们观察到氮掺杂Gd_2O_3层的漏电流密度显著降低，表明氮掺杂是消除氧化层中氧空位引起的缺陷的不利影响的有效途径。
The dielectric properties of thin crystalline oxides grown on silicon are sensitive to small variations in structure and symmetry. Here, we report about different investigations on strain-induced effects on dielectric properties. First, we report on the dependence of the dielectric constant on layer thickness for epitaxial Gd2O3 on Si (111). The K-value strongly decreases with increasing layer thickness and reaches the bulk value at around 8 nm. Controlling the oxide composition in ternary (Gd1-xNdx) 2O3 thin films enables us to tune the lattice mismatch to silicon, and thus the straininduced variation in the dielectric constants. We show that solely tetragonal distortion of the cubic lattice is not sufficient to explain the huge enhancement in K-values; more severe strain induced structural phase deformations take place. Further, dielectric properties of epitaxial oxide thin films have been found to improve significantly by incorporation of suitable dopants. We observe substantial reduction of the leakage current density in nitrogendoped Gd2O3 layers indicating that nitrogen doping can be an effective route to eliminate the adverse effects of the oxygen vacancy induced defects in the oxide layers.