Effects of post-deposition annealing on BaTiO 3 /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 (BaTiO 3 ) 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 BaTiO 3 films and their impact on the surface and electrical characteristics of MOS capacitors. The crystallinity and surface morphologies of the BaTiO 3 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 BaTiO 3 /4H-SiC and elevated the rectification ratio from 9.12 × 10 8 to 1.61 × 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 × 10 11 to 5.53 × 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 × 10 11 to 3.58 × 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 BaTiO 3 thin film deposition using AD.