Preparation of WN_X Thin Films Using RF-DC Coupled Magnetron Sputtering and Diffusion Barrier Properties for Cu/WN_X/Si Samples

Abstract

Tungsten nitride (WN_X) thin films have been prepared using an RF-DC coupled magnetron sputtering system, in which the incident ion energy on the target can be controlled by the target DC bias voltage. The films were applied to Cu/WN_X/Si samples and the obtained Cu (500 nm) /W₂N (25 nm) /Si samples were stable without Cu-Si reaction after annealing at 700°C for 30 min. It was shown that the film composition (N/W) can be controlled by the target DC bias voltage without changing the gas flow ratio (N₂/ (Ar+ N₂)), and the N/W ratio was decreased from 0.8 to 0.2 only by increasing the target DC bias voltage from -100 V to -500 V, respectively, at the N₂/ (Ar + N₂) ratio of 0.2.