Properties of HfO2/La2O3 nanolaminate films grown on an AlGaN/GaN heterostructure by plasma enhanced atomic layer deposition

Abstract

HfO₂/La₂O₃ nanolaminate (HLOL) films were grown on AlGaN/GaN heterostructure by plasma enhanced atomic layer deposition (PEALD). After high-temperature rapid thermal annealing (RTA), the properties of the films were characterized. Si (coming from the La₂O₃ metal precursor) and La atoms diffuse into the HfO₂ layer, cubic and tetragonal phase HfO₂ exist in the HLOL film. The HLOL film has an effective dielectric constant of 35.7 and a breakdown electric field of 5.5 MV cm⁻¹. Moreover, the HLOL film is an effective barrier to suppress the gate leakage current, which is 5 orders of magnitude lower compared to a conventional Schottky diode. The HLOL dielectric film on AlGaN/GaN could also improve the gate voltage swing range.