Improved Characteristics of 4H-SiC MISFET with AlON/Nitrided SiO2 Stacked Gate Dielectrics
We investigated the impact of a combination treatment of nitrogen plasma exposure and forming gas annealing (FGA) for a thermally grown SiO2 layer on channel electron mobility in 4H-SiC metal-insulator-semiconductor field-effect-transistors (MISFETs) with and without deposited aluminum oxynitride (AlON) overlayers. This treatment was effective for improving the interface properties of nitrided SiO2/SiC structures formed by thermal oxidation in NOx ambient as well as pure SiO2/SiC structures. A channel mobility enhancement was perfectly consistent with a reduction in interface state density depending on the process conditions of the combination treatment, and a peak mobility of 26.9 cm2/Vs was achieved for the MISFETs with the nitrided SiO2 single dielectric layer. Comparable channel mobility was obtained with a gate insulator consisting of the AlON stacked on a thin nitrided SiO2 interlayer, indicating that both the combination treatment and the AlON/SiO2 stacked dielectrics can be integrated into the SiC MISFET fabrication processes.
Anton J. Bauer, Peter Friedrichs, Michael Krieger, Gerhard Pensl, Roland Rupp and Thomas Seyller
T. Hosoi et al., "Improved Characteristics of 4H-SiC MISFET with AlON/Nitrided SiO2 Stacked Gate Dielectrics ", Materials Science Forum, Vols. 645-648, pp. 991-994, 2010