부산대학교 도서관

We report on charge capture and emission in Metal-Oxide-Semiconductor AlGaN/AlN/GaN High-Electron Mobility Transistors (MOS-HEMT) foreseen as power amplifiers in mm-wave user-equipment operating at RF frequencies. These devices target Enhancement mode operation, necessitating the incorporation of high-permittivity $(\mathbf{high}-\boldsymbol{\kappa})$ dielectrics to mitigate barrier thinning induced leakage. It is shown that defects in the bulk of HfO 2 or Al 2 O 3 dielectrics result in significant $\boldsymbol{V_{t}}$ instabilities, with dielectric-dependent charge emission kinetics: band alignment between $\mathbf{high}-\boldsymbol{\kappa}$ shallow defect levels and AlGaN conduction band enables full (Al 2 O 3 ) or partial (HfO 2 ) charge de-trapping, while a deeper level in HfO 2 enables trapping even at threshold conditions. The significance of this work lies in revealing the degradation modes present under DC which can also contribute at RF operating conditions.