The influence of La/Al atomic ratio on the dielectric constant and band-gap of stack-gate La–Al–O/SiO2 structure
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- 作者：Shulong Wang ; Hongxia Liu ; Hailin Zhang
- 刊名：Journal of Materials Science: Materials in Electronics
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：28
- 期：2
- 页码：2004-2008
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Optical and Electronic Materials; Characterization and Evaluation of Materials;
- 出版者：Springer US
- ISSN：1573-482X
- 卷排序：28
文摘
The influence of La/Al atomic ratio on high-dielectric-constant of La–Al–O thin films deposited by atomic layer deposition is investigated. The uniform surface morphology of the bilayer films with different La/Al cycle ratio (La/Al ratio) is observed after rapid thermal annealing. With the help of high-frequency capacitance–voltage measurement, the dielectric constant drops greatly with decreasing La/Al ratio. It is caused by the formation of La(OH)3 in La–Al–O thin film, which has been verified by X-ray photoelectron spectroscopy (XPS) measurement. For the reduced interface dipoles at the high-k/SiO2 interface, the flat band voltage (Vfb) shift is not obvious in La–Al–O film. By ellipsometry measurements, it can be found that the band-gap of the thin film increases with increasing Al component, especially when Al component in La–Al–O gate dielectric is small. The research results here show that lower Al doping in La–Al–O can keep high dielectric constant and relatively large band-gap in the thin film, which is very useful for the high-k process development.