High-Temperature H2- and N2-Containing Surface Conditioning for SiO2/4H-SiC Interface Optimization

In this paper, we study high-temperature H 2 , N 2 , and H 2 /N 2 surface conditioning processes prior to the SiO 2 deposition as a promising approach for SiO 2 /4H-SiC interface preparation in metal-oxide-semiconductor field-effect transistors (MOSFET). A thorough electrical analysis is presented, consisting of temperature-dependent transfer characteristics as well as reliability studies regarding bias temperature instabilities (BTI) and dielectric breakdown behavior. Especially N 2 -containing surface pretreatments were found to greatly suppress electron traps, whereas hole trapping is enhanced. Finally, X-ray photoelectron spectroscopy (XPS) was utilized to elucidate the elemental surface composition after the different annealing procedures. The obtained results are in good agreement with the electrical characterization and complement already published results regarding the formation of surface reconstructions on 4H-SiC through H 2 and H 2 /N 2 annealings.