Copper nitride (Cu3N) layers exhibit promising physical properties. Their structural and electrical properties are similar to those of semiconductors. However, the chemical and thermal properties of copper nitride remain unresolved. Hence, the objective of this research was to study the influence of the formation process on the structure and thermal properties of Cu3N.
We investigated N-rich copper nitride thin films before and after annealing. The morphology and structural properties of these films were analyzed by XRD and AFM. These studies were performed at different flow rates and partial pressures. The results were in agreement with the theoretical predictions.
Our results showed that the concentration of reactive nitrogen species decreased with increasing target-substrate distance. This decrease could be caused by a decrease in the activity of N2 in the gas-phase recombination of sputtered N species.
The growth chemistry of copper nitride was studied at various substrate temperatures and target-substrate distances. For example, a change in the distance of the target-substrate was measured in order to identify the critical decomposition temperature of the material.
The result showed that a large amount of Cu and N atoms formed an N-rich orientation at a higher N2 partial pressure. This N-rich phase exhibited a large lattice constant and retained a cubic structure.
The grain size of Cu3N thin films was also studied. The results showed that the smallest grains were observed at the shortest target-substrate distance. High partial pressures increased the size of the grains, which resulted in a sharp grain boundary.