A WSIXN DIFFUSION BARRIER FORMED WITH ELECTRON-CYCLOTRON-RESONANCE NITROGEN PLASMA

The effectiveness of using a tungsten silicon nitride (WSixN) layer as a dopant diffusion barrier is investigated. The WSixN layer can be fo rmed by simple WSix surface nitridation using electron cyclotron reson ance (ECR) plasma of nitrogen gas without substrate heating. Structura l analysis reveals that the WSixN layer is very thin (5.0 to 6.0 nm) a nd that it remains intact and has an amorphous structure free from gra in boundaries even after annealing at 850 degrees C. The WSixN layer f ormed with ECR nitrogen plasma is found to act as an excellent barrier to dopant diffusion.