Atomic Layer Deposition of Low-Resistivity and High-Density Tungsten Nitride Thin Films Using B[sub 2]H[sub 6], WF[sub 6], and NH[sub 3]

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.