Quantitative characterization of interface traps in Al2O3/AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors by dynamic capacitance dispersion technique

Abstract

In this letter, the interface traps of Al₂O₃/AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) were characterized quantitatively by dynamic capacitance dispersion technique. An analysis of Al₂O₃/AlGaN interface states demonstrated deep traps in the range of 0.53 eV-1.16 eV below the conduction band, with trap density nearly constant and two orders of magnitude smaller than that at AlGaN surface due to the use of atomic layer deposition-grown Al₂O₃ insulator. As much as 2.23 × 10¹³ eV⁻¹ cm⁻² fast traps with time constant smaller than 0.3 μs were observed at AlGaN/GaN interface of MOS-HEMTs, which was consistent with the qualitative prediction from pulsed I-V test.