When a Schottky diode experiences enough degradation to cause the post-irradiation electrical parameter measurements to be out of specification, failure analysis appears to show that the damage occurs solely at the Schottky metal/silicon interface. This is in contrast to when a diode fails catastrophically. In that case, the event appears to also begin at the metal/silicon junction, however, the event generates such extreme heat that the materials become molten. A filament is then created that displaces the metal into the bulk silicon and can also displace silicon to the surface of the diode. This filament shorts the anode (bulk silicon) to the cathode (Schottky barrier metal) and the current is only limited by the power supply.To avoid these radiation responses in which the diode is operating outside of the manufacturer's specifications, a reverse voltage derating of 50% is recommended when testing will not be conducted. If testing will be conducted on the flight diodes under the application-specific bias conditions, then a derating similar to power MOSFETs is recommended, in which the maximum reverse voltage that may be used is 75% of the last passing voltage.In this work, we use high-and low-magnitude optical microscope images, infrared camera images, and scanning electron microscope images to identify and describe the failure locations in heavy-ion-irradiated Schottky diodes.