【Device Papers】Low leakage current β-Ga₂O₃ MOS capacitors with ALD deposited Al₂O₃ gate dielectric using Ozone as precursor

      Researchers from the Sun Yat-Sen University have published a dissertation titled "Low leakage current β-Ga₂O₃ MOS capacitors with ALD deposited Al₂O₃ gate dielectric using Ozone as precursor" in Chinese Physics B.

Abstract

      Metal–insulator–semiconductor (MOS) capacitor is a key structure for high performance MOS field transistors (MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga₂O₃ MOS capacitors were fabricated with ALD deposited Al₂O₃ using H₂O or ozone (O₃) as precursors. Compared with the Al₂O₃ gate dielectric with H₂O as ALD precursor, the leakage current for the O₃ precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al₂O₃ with O₃ as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al₂O₃ with O₃ precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al₂O₃/β-Ga₂O₃ MOS capacitor using the O₃ precursor has a low leakage current and holds potential for application in β-Ga₂O₃ MOSFETs.

DOI：

https://doi.org/10.1088/1674-1056/adc660