High Breakdown Electric Field Diamond Schottky Barrier Diode With SnO₂ Field Plate

Diamond is desirable for the application in power device due to its extremely high theoretical breakdown electric field (>10 MV/cm). However, because of electric field crowding, relatively low experimental results of breakdown electric field were attained. The vertical diamond with SnO2 field plate (FP) exhibiting excellent performance was fabricated. SnO2 deposited by electron beam evaporation with high dielectric constant of 17 possesses the potential to alleviate crowding field at the edge of Schottky electrodes. The SnO2 FP SBD shows high breakdown electric field of 4.04 MV/cm and high breakdown voltage of 185 V, which is 69.7% higher than diamond SBD without FP. The suppression of leakage current can also be observed in SBD with SnO2 FP. The edge electric field crowding of Schottky contact has been mitigated effectively by FP structure. Meanwhile, the FP SBD can still maintain low differential resistance of 1.31 $\text{m}\Omega \cdot \text {cm}^{{2}}$ , high forward current of 4740 A/cm2, unchanged Schottky barrier height, and ideality factor. It is suggested that SnO2 FP structure is a good method to improve reverse characteristics without compromising the forward performance of SBD, and this FP enables diamond SBD potential for power electronic devices.