Effect of OH on chemical mechanical polishing of β-GaO (100) substrate using an alkaline slurry.
Chuanjin Huang, Wenxiang Mu, Hai Zhou, Yongwei Zhu, Xiaoming Xu, Zhitai Jia, Lei Zheng, Xutang Tao
Author Information
Chuanjin Huang: College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics Nanjing 210016 China meeywzhu@nuaa.edu.cn. ORCID
Wenxiang Mu: State Key Laboratory of Crystal Materials, Key Laboratory of Functional Crystal Materials and Device, Shandong University Jinan 250100 China txt@sdu.edu.cn.
Hai Zhou: College of Mechanical Engineering, Yancheng Institute of Technology Yancheng 224051 China.
Yongwei Zhu: College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics Nanjing 210016 China meeywzhu@nuaa.edu.cn.
Xiaoming Xu: College of Mechanical Engineering, Yancheng Institute of Technology Yancheng 224051 China.
Zhitai Jia: State Key Laboratory of Crystal Materials, Key Laboratory of Functional Crystal Materials and Device, Shandong University Jinan 250100 China txt@sdu.edu.cn.
Lei Zheng: College of Mechanical Engineering, Yancheng Institute of Technology Yancheng 224051 China.
Xutang Tao: State Key Laboratory of Crystal Materials, Key Laboratory of Functional Crystal Materials and Device, Shandong University Jinan 250100 China txt@sdu.edu.cn. ORCID
β-GaO, a semiconductor material, has attracted considerable attention given its potential applications in high-power devices, such as high-performance field-effect transistors. For decades, β-GaO has been processed through chemical mechanical polishing (CMP). Nevertheless, the understanding of the effect of OH on β-GaO processed through CMP with an alkaline slurry remains limited. In this study, β-GaO substrates were successively subjected to mechanical polishing (MP), CMP and etching. Then, to investigate the changes that occurred on the surfaces of the samples, samples were characterised through atomic force microscopy (AFM), three-dimensional laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). LSCM and SEM results showed that β-GaO is highly vulnerable to brittle fracture during MP. AFM revealed that an ultrasmooth and nondamaged surface with a low of approximately 0.18 nm could be obtained through CMP. XPS results indicated that a metamorphic layer, which mainly contains soluble gallium salt (Ga(OH) ), formed on the β-GaO surface through a chemical reaction. A dendritic pattern appeared on the surface of β-GaO after chemical etching. This phenomenon indicated that the chemical reaction on the β-GaO surface occurred in a nonuniform and selective manner. The results of this study will aid the optimization of slurry preparation and CMP.
