Influence of annealing on structural and electrical properties of double metal structure Ru/Cu contacts on n‐type InP

In this article, we have investigated the effects of rapid thermal annealing on the electrical and structural properties of Ru/Cu Schottky contacts on n‐InP by current density–voltage ( J – V ), capacitance–voltage ( C – V ), Secondary ion mass spectrometer (SIMS) and X‐ray diffraction (XRD) measurements. The Schottky barrier height (SBH) of the as‐deposited Ru/Cu Schottky contact is found to be 0.65 eV ( I – V ) and 0.84 eV ( C – V ), respectively. The obtained barrier height values 0.81 eV ( I – V ), 0.95 eV ( C – V ) at 100 °C, 0.85 eV ( I – V ), 1.02 eV ( C – V ) at 200 °C, 0.80 eV ( I – V ), 0.90 eV ( C – V ) at 300 °C and 0.75 eV ( I – V ), 0.88 eV ( C – V ) at 400 °C. It is observed that the SBH increases with annealing temperature up to 200 °C. Further, increase in the annealing temperature up to 400 °C, SBH decreases compared to the one at 200 °C annealed samples. Norde method is also used to calculate the barrier height of Ru/Cu Schottky contact. Based on the above results, the optimum annealing temperature for the Ru/Cu Schottky contact is 200 °C. According to SIMS and XRD results, the formation of indium phases at the interface may be the reason for the increase of barrier height after annealing at 200 °C. The AFM results showed that the overall surface morphology of Ru/Cu Schottky contact is fairly smooth even after annealing at 400 °C.