Isotropic performance of surface acoustic wave resonators based on ε-Ga2O3(001) thin films

IF 6.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Applied Surface Science Pub Date : 2025-07-01 DOI:10.1016/j.apsusc.2025.163959

Junhao Chen , Chenhong Huang , Tiecheng Luo , Yujia Tu , Xifu Chen , Zhuo Yang , Hongtai Luo , Gang Wang , Xing Lu , Zimin Chen

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Abstract

Epsilon-phase gallium oxide (ε-Ga₂O₃) thin film is an emerging piezoelectric semiconductor for the application in RF resonators. Compared with traditional thin films such as AlN (d₃₃≈5 pm/V), ε-Ga₂O₃ possesses a high piezoelectric coefficient (d₃₃≈11 pm/V). As a material belonging to the orthorhombic crystal system, ε-Ga₂O₃ is theoretically expected to exhibit anisotropic properties on the (001) plane. However, in this study, a comprehensive investigation on the angular dependence of surface acoustic wave (SAW) propagation properties reveals that the ε-Ga₂O₃(001) plane is actually highly isotropic. Measurements of electrostatic, mechanical, and thermomechanical characteristics along different in-plane directions on ε-Ga₂O₃(001) present standard deviation smaller than 3 %. The dielectric constant of ε-Ga₂O₃ is extracted to be 11.7 ± 0.1 by the capacitance measurement. Phase velocity and the temperature coefficient of frequency (TCF) for ε-Ga₂O₃ SAW resonators are determined to be 3169 ± 4 m/s and −58.9 ± 1.7 ppm/°C for Rayleigh mode, while it is 5319 ± 11 m/s and −58.9 ± 1.2 ppm/°C for Sezawa mode. The abnormal isotropy of the orthorhombic ε-Ga₂O₃ is explained by the existence of triple rotational domains. The results provide critical basic parameters for the future development and application in ε-Ga₂O₃-based SAW devices.

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基于ε-Ga2O3（001）薄膜表面声波谐振器的各向同性性能

ε相氧化镓（ε-Ga2O3）薄膜是一种新兴的用于射频谐振器的压电半导体材料。与AlN （d33≈5 pm/V）等传统薄膜相比，ε-Ga2O3具有较高的压电系数（d33≈11 pm/V）。作为正交晶系材料，ε-Ga2O3在（001）平面上表现出各向异性。然而，在本研究中，对表面声波（SAW）传播特性的角依赖性的综合研究表明，ε-Ga2O3（001）面实际上是高度各向同性的。在ε-Ga2O3（001）上沿不同面内方向测量的静电、力学和热力学特性的标准差小于3 %。通过电容测量得到ε-Ga2O3的介电常数为11.7 ± 0.1。相速度和频率温度系数(TCF)ε-Ga2O3谐振器被确定为3169年 ± 4 m / s, 58.9− ±1.7  ppm /°C为瑞利模式,虽然5319年 ± 11 m / s, 58.9− ±1.2  ppm /°C Sezawa模式。正交型ε-Ga2O3的反常各向同性可以用三转动畴的存在来解释。研究结果为ε- ga2o3基SAW器件的未来发展和应用提供了关键的基础参数。

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来源期刊

Applied Surface Science 工程技术-材料科学：膜

CiteScore

12.50

自引率

7.50%

发文量

3393

审稿时长

67 days

期刊介绍： Applied Surface Science covers topics contributing to a better understanding of surfaces, interfaces, nanostructures and their applications. The journal is concerned with scientific research on the atomic and molecular level of material properties determined with specific surface analytical techniques and/or computational methods, as well as the processing of such structures.