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

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 (N₂, N₂O, 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 N₂O and NO, respectively, whereas BJTs having conventional thermally grown oxides showed a current gain of 50.