Reduction in Shottky barrier height of AlGaN-based SBD with in-situ deposited silicon carbon nitride (SiCN) cap layer

AlGaN/GaN Schottky barrier diodes (SBDs) with and without in-situ silicon carbon nitride (SiCN) cap layer were investigated. The fabricated SBD with SiCN cap layer exhibited improved electrical characteristics, such as the forward turn on voltage of about 0.7 V, the forward current of 4.1 A at 1.5 V, and the reverse breakdown voltage of 630 V, compared to the corresponding values of 0.8 V, 3.8 A, and 580 V for the reference SBD without the SiCN cap layer. This improvement in the device performance of the SiCN-SBD is because the in-situ SiCN cap layer not only lowers the barrier height, but also effectively passivates the surface of the device with better surface morphology.