Temperature-Dependent Elemental Diffusion at the Ta/O-Diamond Interface Under Low-Oxygen Conditions

Diamond is an ideal semiconductor for high-temperature, high-voltage applications due to its wide band gap, high carrier mobility, and high thermal conductivity. Diamond Schottky barrier diodes (SBDs) have been intensively developed; however, their thermal stability has not been explored comprehensively. Considering that the diamond/metal interface is one key factor affecting the thermal stability, in this work, we employed tantalum (Ta)/oxygen-terminated (O-) diamond system and investigated the impact of annealing temperature (300°C, 600°C, 900°C, and 1200°C) on chemical and structural evolution of the Ta/O-diamond interface under low-oxygen ambient. Angle-resolved X-ray photoelectron spectroscopy (ARXPS) and atomic force microscopy (AFM) were performed to examine the interface reactions and surface morphologies. Furthermore, the possible mechanism of the interface evolution under low-oxygen ambient was discussed. This work provides insights into understanding the interface evolution and thus the thermal stability Ta/O-diamond.