Copper diffusion in amorphous thin films of 4% phosphorus-silcate glass and hydrogenated silicon nitride

We have carried out direct Cu diffusion measurements in amorphous thin films of: (a) 4% phosphorus silicate glass and (b) hydrogenated silicon nitride. Thin films of 0.5 μm thickness were grown onto oxidized Si wafers by a chemical vapor deposition technique. 67Cu radiotracer diffusion techniques combined with microdepth profiling by sputtering with neutralized Ar atoms of 400-500 eV energy have been used. The 67Cu diffusion coefficients in 4% P-Si glass and in SiN at. % H films in the temperature range of 227-550°C are described by: (a) 5.3 ×10-11 exp (-0.5 eV/kT) and (b) 4×10-6 exp (-1.1 eV/kT) cm2/s, respectively. To assure reliability, the extent of Cu diffusion should be considered in device design and subsequent processing.