| 초록 |
Tungsten nitride(WNx) thermal CVD process has been studied for Cu diffusion barrier. W(CO)6 and NH3 were used for tungsten source and nitrogen source respectively. W(CO)6 was introduced into the reactor chamber using bubbler with Ar as a carrier gas. Silicon dioxide was used as substrate and growth temperature was 200-500℃, Ar flow rate was 10 sccm and NH3 flow rate was 10-100 sccm. At below 230℃, film deposition rate was too slow to be analyzed. According to XPS, AES, XRD, RBS, SEM results, all deposited films between 240 and 500℃ were W2N, irrespective of NH3 / W(CO)6 flow ratio. Carbon and oxygen content in grown film were about 4% each at 500℃, and about 10% each at below 300℃ - they seem to remain as carbon monoxide(CO). Resistivity was 500-600μΩ㎝ at above 500℃, and about 900 μΩ㎝ at 250 - 400℃. As deposition temperature decreased, the film changed from polycrystalline structure to amorphous-like structure. A amorphous-like structure is expected to have better diffusion barrier property.
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