Effects of post-deposition annealing on BaTiO₃/4H-SiC MOS capacitors using aerosol deposition method

High-k oxide materials for metal-oxide-semiconductor field-effect transistors and metal-oxide-semiconductor (MOS) structure on SiC have been explored to enhance SiC-based device performance. In our experiments, the MOS capacitors with a high-k barium titanate (BaTiO3) insulating layer were fabricated using the aerosol deposition (AD) method, and post-deposition annealed in O-2 atmospheres. We examined the effects of post-deposition annealing on the BaTiO3 films and their impact on the surface and electrical characteristics of MOS capacitors. The crystallinity and surface morphologies of the BaTiO3 films were analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and atomic force microscopy. We conducted the electrical analysis through current-voltage and capacitance-voltage (C-V) measurements. The post-deposition annealing process effectively reduced the gate leakage current of BaTiO3/4H-SiC and elevated the rectification ratio from 9.12 x 10(8) to 1.61 x 10(9). C-V characteristics were measured at 1 MHz to investigate the oxide defect charges inside the MOS capacitors. Near-interface trap density (N-it) decreased from 9.10 x 10(11) to 5.53 x 10(11) cm(-2) due to post-annealing, which diminished flat band voltage hysteresis. Fixed oxide charge density (Q(f)) also diminished from 4.00 x 10(11) to 3.58 x 10(11) cm(-2), and the oxygen vacancies were compensated by the oxygen atoms introduced from the O-2 during the post-deposition annealing. Our findings suggest that the post-deposition annealed process significantly influences surface and electrical properties during BaTiO3 thin film deposition using AD.