Structure and chemistry of passivated SiC/SiO₂ interfaces

Here, we report on the chemistry and structure of 4H-SiC/SiO₂ interfaces passivated either by nitric oxide annealing or Ba deposition. Using aberration corrected scanning transmission electron microscopy and spectroscopy, we find that Ba and N remain localized at SiC/SiO₂ interface after processing. Further, we find that the passivating species can introduce significant changes to the near-interface atomic structure of SiC. Specifically, we quantify significant strain for nitric oxide annealed sample where Si dangling bonds are capped by N. In contrast, strain is not observed at the interface of the Ba treated samples. Finally, we place these results in the context of field effect mobility.