Identification and Suppression of Majority Surface States in the Dry-Etched β-Ga2O3

Zhengpeng Wang; Xinxin Yu; Hehe Gong; Tiancheng Hu; Yijun Zhang; Xiaoli Ji; Fangfang Ren; Shulin Gu; Youdou Zheng; Rong Zhang; Andrej Yu Kuznetsov; Jiandong Ye

doi:10.1021/acs.jpclett.2c02167

Identification and Suppression of Majority Surface States in the Dry-Etched β-Ga₂O₃

J Phys Chem Lett. 2022 Aug 4;13(30):7094-7099. doi: 10.1021/acs.jpclett.2c02167. Epub 2022 Jul 28.

Authors

Zhengpeng Wang^{1

2}, Xinxin Yu^{1

2}, Hehe Gong^{1

2}, Tiancheng Hu^{1

2}, Yijun Zhang^{1

2}, Xiaoli Ji^{1

2}, Fangfang Ren^{1

2}, Shulin Gu^{1

2}, Youdou Zheng^{1

2}, Rong Zhang^{1

2}, Andrej Yu Kuznetsov³, Jiandong Ye^{1

2

4}

Affiliations

¹ School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China.
² Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
³ Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo, Norway.
⁴ Shenzhen Research Institute of Shandong University, Shenzhen 518000, China.

PMID: 35900195
DOI: 10.1021/acs.jpclett.2c02167

Abstract

Surface treatment after dry etching is vital to enhance the surface quality of the material and thus improve device performance. In this Letter, we identified the majority surface states induced by the dry etching of β-Ga₂O₃ and optimized surface treatments to suppress these electrically active defects with the improved performance of Schottky barrier diodes. Transient spectroscopies suggested that the majority traps (E_C-0.75 eV) related to divacancies (V_Ga-V_O) were enhanced in the concentration of 3.37 × 10¹⁴ cm^-3 by dry etching and reduced to 0.90 × 10¹⁴ cm^-3 by the combined means of oxygen annealing and piranha solution treatment. The trap evolution is supported by the suppressed donor-acceptor pair radiative recombination related to oxygen vacancies, the improved carrier transport (negligible hysteresis current-voltage and unity ideality factor), and the reduced surface band bending. These findings provide a straightforward strategy to improve surface quality for the further performance improvement of Ga₂O₃ power diodes.