Atomic composition of WC/ and Zr/O-terminated diamond Schottky interfaces close to ideality

Abstract

Electrical and nano-structural properties of Zr and WC-based Schottky power diodes are compared andused for investigating oxide-related effects at the diamond/metal interface. Differences in Schottky bar-rier heights and ideality factors of both structures are shown to be related with the modification of theoxygen-terminated diamond/metal interface configuration. Oxide formation, oxide thickness variationsand interfacial oxygen redistribution, associated with thermal treatment are demonstrated. Ideality fac-tors close to ideality (nWC= 1.02 and nZr= 1.16) are obtained after thermal treatment and are shown to berelated with the relative oxygen content at the surface (OCRWC= 3.03 and OCRZr= 1.5). Indeed, thermaltreatment at higher temperatures is shown to promote an escape of oxygen for the case of the WC diode,while it generates a sharper accumulation of oxygen at the metal/diamond interface for the case of Zrdiode. Therefore, the metal-oxygen affinity is shown to be a key parameter to improve diamond-basedSchottky diodes.