Enhanced quality of Al 2 O 3 /SiC gate stack via microwave plasma annealing

Abstract The high‐quality gate dielectric on silicon carbide (SiC) surface is critical to fabricate high‐performance SiC metal–oxide–semiconductor field‐effect transistors (MOSFETs). This research employs microwave plasma annealing (MPA) to obtain high‐quality Al 2 O 3 /SiC gate stacks. By designing MPA atmosphere and optimizing the plasma power, the SiC MOS capacitor with a Al 2 O 3 dielectric film shows the enhanced performance. The interface state density is reduced by 1 order of magnitude to 6 × 10 11 cm −2 ·eV −1 , the breakdown electric field is increased, and the voltage shift is effectively suppressed. Besides, the mechanism of MPA process is discussed in terms of the thermal effect and reactant species. X‐ray photoelectron spectroscopy (XPS) results unveil oxygen plasma plays the main role. Optimal plasma power during the MPA process results in defect repairs of the first‐neighbor Al–O bonding and partial removal of Al–O–H bond from the interface region. This study demonstrates that MPA process is an effective option to realize high‐quality dielectric and interface on SiC.