1：Experimental Design and Method Selection:

Two sets of n-type 4H-SiC MIS capacitors were made, one with single crystalline AlN and the other with amorphous Al2O3 as a dielectric. The interface quality was characterized by capacitance-voltage (CV) analysis, and dielectric breakdown strength was determined by current-voltage (IV) measurements.

2：Sample Selection and Data Sources:

The 4H-SiC used had 10 μm thick n-type epitaxial layers with a net doping concentration of ～ 1 × 10^16 cm^-3 grown on 4° off-axis (0001) highly doped ～ 1 × 10^18 cm^-3 4H-SiC substrates.

3：List of Experimental Equipment and Materials:

Equipment included a horizontal hot-wall MOCVD reactor, electron beam evaporation system, hot plate, plasma enhanced chemical vapor deposition (PECVD) system, Agilent E4980A LCR meter, Keithley 617 electrometer, X-ray reflectivity (XRR), Atomic Force Microscopy, X-ray diffraction (XRD), and a cryostat. Materials included AlN, Al2O3, SiO2, Al gate metal, ammonia, Al2(CH3)6, HF, nitrous oxide, and silane.

4：Experimental Procedures and Operational Workflow:

AlN was grown by MOCVD at 1100°C after H2 ambient exposure at 1320°C. Al2O3 was grown by repeated Al deposition via electron beam evaporation and oxidation on a hot plate at 200°C. Additional SiO2 was deposited by PECVD at 300°C on selected samples. Circular MIS capacitors were fabricated with Al gates. CV and IV measurements were performed in vacuum at 10^-3 mbar.

5：Data Analysis Methods:

Interface trap density (Dit) was extracted using the High-Low-Capacitance method from CV dispersion data. Dielectric breakdown field was estimated from J-E curves.