Shallow Traps at P-Doped SiO2/4H-SiC(0001) Interface

Abstract

We report on electrical and physical investigations aimed to clarify the mechanisms behind the high channel mobility of 4H-SiC metal–oxide–semiconductor field-effect transistors processed with POCl3 annealing. By low-temperature capacitance–voltage analysis, we found that the shallow interface traps are effectively removed by P incorporation. Using x-ray photoelectron spectroscopy, we found that the three-fold coordinated P atoms exist at the oxide/4H-SiC interface. The overall results suggest that P atoms directly remove the Si–Si bonds and thus eliminate the near-interface traps.