Enhanced Inversion Mobility on 4H-SiC $(\hbox{11}\overline{\hbox{2}} \hbox{0})$ Using Phosphorus and Nitrogen Interface Passivation

Abstract

Low interface trap density and high channel mobility on nonpolar faces of 4H-SiC, such as the (11[2̅]0) a-face, are of fundamental importance in the understanding of SiC MOS devices. It is also critical for high-voltage trench power MOSFET development. We report new results on the passivation of the SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /a-face 4H-SiC interface using phosphorus, yielding field effect mobility of ~125 cm <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /V · s. We also revisit the conventional NO passivation, for which a mobility of ~85 cm <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /V · s was achieved on the a-face. These results not only establish new levels of mobility in SiC MOSFETS but also lead to further insights into factors currently limiting SiC inversion layer mobility.