Growth of Bi2O3 Ultrathin Films by Atomic Layer Deposition
Growth of Bi2O3 Ultrathin Films by Atomic Layer Deposition
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DOI：
10.1021/jp205180p
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发表时间：
2012-01
影响因子：
3.7
通讯作者：
Yue Shen;Yuan Li;W. M. Li;Jinzhong Zhang;Ziyu Hu;J. Chu
中科院分区：
文献类型：
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作者：
Yue Shen;Yuan Li;W. M. Li;Jinzhong Zhang;Ziyu Hu;J. Chu
以Bi（thd）3（thd：2，2，6，6-四甲基-3，5-庚二酮）和水为前驱体，采用原子层沉积法（ALD）在硅衬底上成功地制备了三氧化二铋（Bi 2 O3）薄膜。最佳ALD窗口约为270-300 °C，并确定了通过表面饱和反应的ALD型生长机制;生长速率约为0.1 A/循环。X射线衍射和高分辨率透射电子显微镜研究表明，Bi 2 O3薄膜在250 °C以上结晶成主要的α相。室温电阻率约为1.2 × 106 Ω·cm，这也证明了沉积态Bi 2 O3薄膜的α相结构。此外，还发现了一种制备γ-Bi_2O_3薄膜的新方法。ALD法制备的α-Bi 2 O3薄膜在512 °C以上退火后转变为具有（222）择优取向的亚稳态γ-Bi 2 O3，γ相在室温下仍能保持。
Bismuth trioxide (Bi2O3) ultrathin films were successfully synthesized on silicon substrates by means of atomic layer deposition (ALD) using Bi(thd)3 (thd: 2,2,6,6-tetramethyl-3,5-heptanedionato) and H2O as precursors. The optimum ALD window was about 270–300 °C, and an ALD-type growth mechanism via surface saturation reaction was identified; the growth rate was about 0.1 A/cycle. The X-ray diffraction and high-resolution transmission electron microscopy investigation revealed that Bi2O3 films crystallized into a predominant alpha phase above 250 °C. The resistivity at room temperature was about 1.2 × 106 Ω·cm, which is also proof of the α-phase of as-deposited Bi2O3 films. In addition, a new method to obtain γ-Bi2O3 film was discovered. The α-Bi2O3 films (synthesized by ALD) transformed into metastable γ-Bi2O3 with preferred orientation (222) after annealing above 512 °C, and γ-phase could persist at room temperature.