【Device Papers】Characteristics of β-Ga₂O₃/Al₂O₃/Pt Capacitors with a Ga₂O₃ Surface Modified Using the Dummy-SiO₂ Process

      Researchers from NIMS have published a dissertation titled " Characteristics of β-Ga₂O₃/Al2O3/Pt Capacitors with a Ga₂O₃ Surface Modified Using the Dummy-SiO2 Process " in ECS Journal of Solid State Science and Technology.

Abstract

      The characteristics of β-Ga₂O₃/Al₂O₃/Pt capacitors fabricated via the dummy-SiO₂(d-SiO₂) process at 800°C under O₂ (D-O₂), N₂ (D-N₂), and 3% H₂ (D-H₂) atmospheres were investigated. The surface of Ga₂O₃ after the d-SiO₂ process was as smooth as that after the sulfuric acid-hydrogen peroxide mixture treatment (Control). The flatband voltage (V_fb) hysteresis decreased as follows: Control (0.76 V) > D-H₂ (0.56 V) > D-N₂ (0.43 V) > D-O₂ (0.37 V). The interface state density of the D-O₂ capacitor was significantly reduced to 6 × 10¹¹ cm⁻²eV⁻¹ at -0.4 eV from conduction band. The V_fb shift caused by the electron traps according to the near-interface trap model under positive bias stress substantially improved for the capacitors fabricated by the d-SiO₂ process. The poor characteristics of the Control capacitor are due to the presence of the unstable layer on the Ga₂O₃ surface. The improved electrical characteristic of the d-SiO₂ capacitors is due to the modified Ga₂O₃ surface, which eliminated the unstable Ga₂O₃ layer. This is the result of hydrogen contained within the dummy SiO₂ layer supporting the removal of Ga₂O₃. The difference in the decomposition reaction of Ga₂O₃ due to the atmosphere gas of the d-SiO₂ process leads to differences in electrical properties.

DOI：

https://doi.org/10.1149/2162-8777/ae7ac0