Improvement of Current Gain in 4H-SiC BJTs by Surface Passivation With Deposited Oxides Nitrided in $\hbox{N}_{2}\hbox{O}$ or NO

Abstract

We report the improvement of current gain in 4H-SiC bipolar junction transistors (BJTs) by utilizing deposited oxides as a surface passivation layer. Various post deposition annealing processes, including annealing ambient (N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O, and NO) and annealing time, were investigated. We successfully demonstrate SiC BJTs with high current gains (β) of 73 and 102 using deposited oxides annealed in N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O and NO, respectively, whereas BJTs having conventional thermally grown oxides showed a current gain of 50.