Breakdown phenomena of Al-based high-k dielectric/SiO2 stack on 4H-SiC

In this report we present the breakdown phenomena of Al-based high-$k$ dielectrics and thermal ${\text{SiO}}_2$ intermediate layer stack on $4H\text{-SiC}$ . The Al-based dielectrics, namely, sputter deposited aluminum nitride $\left({\text{AlN}}_x\right)$ and hydrogenated aluminum nitride $\left({\text{AlN}}_y:\text{H}\right)$ , have been used to form metal-insulator-semiconductor (MIS) capacitors and field-plate terminated Schottky barrier diodes (SBDs) on $4H\text{-SiC}$ . Multistep breakdown modes visible on these devices have been investigated using measurements of dielectric relaxation currents on MIS capacitors.