生长气压对分子束外延β-Ga<sub>2</sub>O<sub>3</sub>薄膜特性的影响

蔡文为; 刘祥炜; 王浩; 汪建元; 郑力诚; 王永嘉; 周颖慧; 杨旭; 李金钗; 黄凯; 康俊勇

人工晶体学报, 2022, 51 (7): 1152, 网络出版: 2022-08-12

生长气压对分子束外延β-Ga₂O₃薄膜特性的影响

Effect of Growth Pressure on Properties of β-Ga₂O₃ Thin Films Grown by Molecular Beam Epitaxy

论文大纲

蔡文为 ^1,*刘祥炜 ¹王浩 ¹汪建元 ¹郑力诚 ¹王永嘉 ¹周颖慧 ¹杨旭 ^1,2李金钗 ^1,2黄凯 ^1,2康俊勇 ¹

作者单位

¹ 厦门大学物理学系，半导体光电材料及其高效转换器件协同创新中心，福建省半导体材料及应用重点实验室，微纳光电子材料与器件教育部工程研究中心，厦门 361005

² 厦门市未来显示技术研究院，嘉庚创新实验室，厦门 361005

摘要

本文采用分子束外延技术在具有6°斜切角的c面蓝宝石衬底上外延β-Ga2O3薄膜，系统研究了生长气压对薄膜特性的影响。X射线衍射谱和表面形貌分析表明，不同生长气压下所外延的薄膜表面平整，均具有(201)择优取向。并且，其结晶质量和生长速率均随生长气压增大而逐渐提高。通过X射线光电子能谱分析发现，生长气压增大使得氧空位的浓度大幅下降，高价态Ga比例增大，最终使得O/Ga原子数之比接近理想Ga2O3材料的化学计量比值。利用Tauc公式和乌尔巴赫带尾模型进行计算，结果表明随着生长气压的增大，样品的光学带隙由4.94 eV增加到5.00 eV，乌尔巴赫能量由0.47 eV下降到0.32 eV，证明了生长气压的增大有利于降低薄膜中的缺陷密度，提高薄膜晶体质量。

Abstract

The effect of growth pressure on the properties of β-Ga2O3 thin films epitaxial on c-plane sapphire substrate with 6° oblique cut angle by plasma-assisted molecular beam epitaxy were systematically studied. All of the epitaxial films present (201) orientated single-crystalline structure with smooth surface morphology. In addition, the crystalline quality and growth rate increase gradually with the increase of the growth pressure, as demonstrated by X-ray diffraction and scanning electron microscopy characterizations. According to the X-ray photoelectron spectroscopy measurement results, the percentage of oxygen vacancy and Ga3+ oxidation states decrease and increase, respectively, with increasing growth pressure, resulting in the increment of atomic ratio of O to Ga. Moreover, through the calculation of Tauc frormula and Urbach tail model, the results show that the optical band gap of the films increase from 4.94 eV to 5.00 eV, while Urbach energy decreases from 0.47 eV to 0.32 eV. These results suggest that the crystal quality and optical property of β-Ga2O3 were improved by increasing the growth pressure.

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蔡文为, 刘祥炜, 王浩, 汪建元, 郑力诚, 王永嘉, 周颖慧, 杨旭, 李金钗, 黄凯, 康俊勇. 生长气压对分子束外延β-Ga₂O₃薄膜特性的影响[J]. 人工晶体学报, 2022, 51(7): 1152. CAI Wenwei, LIU Xiangwei, WANG Hao, WANG Jianyuan, ZHENG Licheng, WANG Yongjia, ZHOU Yinghui, YANG Xu, LI Jinchai, HUANG Kai, KANG Junyong. Effect of Growth Pressure on Properties of β-Ga₂O₃ Thin Films Grown by Molecular Beam Epitaxy[J]. Journal of Synthetic Crystals, 2022, 51(7): 1152.

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