The influence of varying the emitter-base geometry, i.e., the emitter width (WE), emitter contact–emitter edge distance (Wn), and base contact–emitter edge (Wp) on the on-state characteristics in 5.6 kV implantation free 4H-SiC BJTs are investigated. The BJTs present a clear emitter size effect pointing out that surface recombination has a significant influence on current gain (β). The results show that the influence of varying Wp on the β is higher than Wn. A distance of 3 μm between emitter contact and base contact to the emitter edge (Wn = Wp = 3 μm) is the optimized value to have a BJT with a high β, and low on-resistance (RON) at a given WE.