Cluster-preforming-deposited amorphous WSin (n = 12) insertion film of low SBH and high diffusion barrier for direct Cu contact

The insertion of an amorphous WSi_n (n = 12) film composed of W-atom-encapsulated Sin cage clusters is demonstrated to reduce the SBH to 0.32 eV at W/n-Si and to 0.51 eV at W/Ge/p-Si junctions, while significantly extending the estimated TDDB lifetime to > 10 years at 100 °C under 5 MV/cm stress for Cu MOS capacitors. This film was formed with an excellent contact hole coverage by using WF6 and SiH4 gas sources in a hot-wall thermal reactor. These film properties enable the direct Cu contact at S/D in CMOS.