Role of film stoichiometry and interface quality in the performance of (Ba,Sr)TiO3 tunable capacitors with high figures of merit
Role of film stoichiometry and interface quality in the performance of (Ba,Sr)TiO3 tunable capacitors with high figures of merit
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DOI：
10.1063/1.4967374
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发表时间：
2016-11
影响因子：
4
通讯作者：
Christopher R. Freeze;S. Stemmer
中科院分区：
文献类型：
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作者：
Christopher R. Freeze;S. Stemmer
采用混合分子束外延技术在Pt底电极上生长Ba0.3Sr0.7TiO3（BST）薄膜，制备了品质因数超过1000的平行板电容器。薄膜的化学计量的影响进行了研究，通过改变（Ba + Sr）/Ti比周围的化学计量组成。质量因子是最高的化学计量的膜，但（Ba + Sr）丰富的膜可以被偏置到更高的领域。此外，使用两种不同的工艺来存款平行板电容器的顶部电极。虽然顶部接触/BST界面的质量没有强烈影响器件的品质因数，但对于具有在高温下沉积的顶部电极的电容器，可以看到介电可调谐性的增强，这有效地去除了界面污染层。
Parallel plate capacitors with quality factors exceeding 1000 were fabricated using Ba0.3Sr0.7TiO3 (BST) thin films grown by hybrid molecular beam epitaxy on epitaxial Pt bottom electrodes. The influence of film stoichiometry was investigated by varying the (Ba + Sr)/Ti ratio around the stoichiometric composition. The quality factor is highest for stoichiometric films, but (Ba + Sr)-rich films can be biased to higher fields. Furthermore, two different processes were used to deposit the top electrodes of the parallel plate capacitors. While the quality of the top contact/BST interface did not strongly affect the device quality factor, an enhancement in the dielectric tunability was seen for capacitors with top electrodes deposited at high temperatures, which effectively removes interfacial contamination layers.