Diffusion Barrier Characteristics of WSiN Films

Abstract

WSiN films were produced through hybrid pulse direct current/radio frequency magnetron co-sputtering and evaluated as diffusion barriers for Cu metallization. The Cu/WSiN/Si assemblies were annealed for 1 h in a vacuum at 500–900 °C. The structural stability and diffusion barrier performance of the WSiN films were explored through X-ray diffraction, Auger electron spectroscopy, and sheet resistance measurement. The results indicated that the Si content of WSiN films increased from 0 to 9 at.% as the power applied to the Si target was increased from 0 to 150 W. The as-deposited W76N24, W68Si0N32, and W63Si4N33 films formed a face-centered cubic W2N phase, whereas the as-deposited W59Si9N32 film was near-amorphous. The lattice constants of crystalline WSiN films decreased after annealing. The sheet resistance of crystalline WSiN films exhibited a sharp increase as they were annealed at 800 °C, accompanied by the formation of a Cu3Si compound. The failure of the near-amorphous W59Si9N32 barrier against Cu diffusion was observed when annealed at 900 °C.

Characterization of ZrBSiTaNx Films

“…Grain boundaries with high defect density provide diffusion paths for elements in crystalline materials, whereas the lack of grain boundaries for amorphous structures improve the diffusion resistance of protective coatings [9][10][11]. Amorphous nitride thin films have been utilized as diffusion barriers in microelectronics [12][13][14], and oxidationresistant coatings for protective purposes at elevated temperatures [11,[15][16][17][18]. The thermal stability of amorphous material in inert gas is crucial in applications such as diffusion barriers.…”