Method of depositing material and semiconductor devices

A method of depositing a transition metal chalcogenide barrier layer, the method comprising:

• providing a substrate having an opening within a dielectric material, into a reaction chamber;
• providing a transition metal precursor in the reaction chamber in vapor phase;
• and
• providing a reactive chalcogen species in the reaction chamber, to thereby deposit the transition metal chalcogenide barrier layer on the dielectric material and within the opening,
• wherein the transition metal chalcogenide barrier layer is between the dielectric material and a conductive metal,
• wherein the chalcogenide comprises one or more of S, Se, and Te,
• wherein the transition metal chalcogenide barrier layer mitigates diffusion between the conductive metal and the dielectric material, and
• wherein the transition metal precursor comprises a transition metal halide or a transition metal oxyhalide.