Degradation and improvement of deep sub-micron contact metallization using selective tungsten CVD

The authors describe the origin of the electrical instability in deep sub-micron tungsten plug contact metallization which is caused by surface electronic structures changing in contact fabrication. They discuss an improvement of deep sub-micron contact metallization using selective W-CVD. It is found that surface inactivation, caused by `contact RIE damage´ and `knocked-on´ oxygen atoms, degrades deep sub-micron contact electrical properties. Controlling the Si surface state by chemical dry etching solves this problem