In this paper, we illustrate the use of RF-sputtered p-NiO to fabricate Junction Termination Extensions (JTEs) for high-performance vertical GaN-on-Si Schottky Barrier Diodes (SBDs). The GaN epitaxial structures were grown on 6-inch Si wafers by MOCVD. The fabricated SBDs with p-NiO JTEs exhibited a low specific on-state resistance of 3 m Omega cm(2) (20% lower than in reference SBDs without JTEs) and their breakdown voltage was improved to 433 V, the highest value ever reported for GaN-on-Si SBDs. Our work shows the great potential of p-NiO to achieve highly effective players for use in vertical GaN power devices.