The influence of geometry of boron implanted guard rings on the characteristics of Schottky diodes on 4H-SiC has been investigated. Results suggest, that whilst the breakdown voltage can be increased, the creation of damage from the implantation process and the additional processing requirements serve to increase the leakage current through the device to unacceptable levels. The leakage current through the terminated diodes is found to be proportional to the diode contact area. At high temperatures the leakage current density of the terminated diodes is equal to unterminated devices suggesting a common mechanism.