Improvement of Current Gain in 4H-SiC BJTs by Surface Passivation With Deposited Oxides Nitrided in N₂O 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.