Atomic layer deposition of low-resistivity and high-density tungsten nitride thin films using B2H6, WF6, and NH3

Abstract

Tungsten nitride thin films were grown by atomic layer deposition using alternating exposures of B2H6, WF6, and NH3 at 300 S C. The film thickness linearly increased with the number of the reaction cycles and the determined growth rate was similar to 0.28 nm/cycle with B2H6, WF6, and NH3 at pulsing times of 5, 0.25, and 2 s, respectively. The film had a resisitivity of similar to 350 mu Omega cm with a metallic W-N bond and density of similar to 15 g/cm(3) at the thickness of 10 nm. X-ray diffractometry analysis showed that the film had nanocrystalline grains with beta-W2N and delta-WN phase. Step coverage was approximately 100% even on the 0.14 mu m diameter contact hole with a 16:1 aspect ratio. (c) 2006 The Electrochemical Society.