New method to suppress encroachment by plasma-deposited β-phase tungsten nitride thin films

Tungsten nitride thin films are prepared with the WF6-NH3-H2 system by the plasma-enhanced chemical vapor deposition method. X-ray diffraction and Auger spectroscopy show that the crystal structure and the composition of tungsten nitride thin films grown at the WF6/NH3 ratio of 1 are β-phase W2N. The resistivity of W2N is about 190–210 μΩ cm and it is demonstrated that severe encroachment and SiO2 etching during the low-pressure chemical vapor deposition of tungsten is remarkably suppressed by the predeposition of W2N.