Improved SiO2/ 4H-SiC Interface Defect Density Using Forming Gas Annealing

We investigated the influence of forming gas annealing (FGA) before and after oxide deposition on the SiO2/4H-SiC interface defect density (Dit). For MOS capacitors (MOSCAPs) that were processed using FGAs at temperatures above 1050°C, CV characterization revealed decreased flat band voltage shifts and stretch-out for different sweep directions and frequencies. Moreover, constant-capacitance deep level transient spectroscopy (CC-DLTS) was performed and showed Dit levels below 1012 cm-2eV-1 for post deposition FGA at 1200°C. Finally, lateral MOSFETs were fabricated to analyze the temperature-dependent threshold voltage (Vth) shift.