Characterization of vertical Mo/diamond Schottky barrier diode from non-ideal I–V and C–V measurements based on MIS model

Abstract

In this study, we investigated non-ideal characteristics of a diamond Schottky barrier diode with Molybdenum (Mo) Schottky metal fabricated by Microwave Plasma Chemical Vapour Deposition (MPCVD) technique. Extraction from forward bias I–V and reverse bias C−2–V measurements yields ideality factor of 1.3, Schottky barrier height of 1.872eV, and on-resistance of 32.63mΩ·cm2. The deviation of extracted Schottky barrier height from an ideal value of 2.24eV (considering Mo workfunction of 4.53eV) indicates Fermi level pinning at the interface. We attributed such non-ideal behavior to the existence of thin interfacial layer and interface states between metal and diamond which forms Metal-Interfacial layer-Semiconductor (MIS) structure. Oxygen surface treatment during fabrication process might have induced them. From forward bias C–V characteristics, the minimum thickness of the interfacial layer is approximately 0.248nm. Energy distribution profile of the interface state density is then evaluated from the forward bias I–V characteristics based on the MIS model. The interface state density is found to be uniformly distributed with values around 1013eV−1·cm−2.