Removal of Crystal Orientation Effects on the Current Gain of 4H-SiC BJTs Using Surface Passivation

In this letter, the dependence of current gain and base resistance on crystal orientations for single-finger 4H-SiC bipolar junction transistors (BJTs) is analyzed. Statistical evaluation techniques were also applied to study the effect of surface passivation and mobility on the performance of the devices. It is shown that BJTs with an emitter edge aligned to the [1210] direction shows a lower current gain before surface passivation and higher base resistance after contact formation compared with other investigated crystal directions. However, the devices show a similar current gain independent of the crystal orientation after surface passivation.