Observation of Interface Defects in Diamond Lateral p-n-Junction Diodes and Their Effect on Reverse Leakage Current

We investigated an effect of interface defects in diamond lateral p-n-junction diodes on their reverse-biased leakage currents. Defects at the p-n interface were observed by cross-sectional transmission electron microscopy from different electron incident directions. The observations revealed that the diodes with the large leakage current had a number of defects localized at the p-n interface. The amount of the defects is related to the magnitude of the reverse leakage currents of the devices. Leakage analysis with applying high voltages strongly suggests that the leakage currents originate from the observed defects. Possible origin of the defect formation is discussed.