Nitridation of fine grain chemical vapor deposited tungsten film as diffusion barrier for aluminum metallization
- Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University and National Nano Device Laboratory, Hsinchu, Taiwan, Republic of (China)
A novel tungsten nitride (WN{sub x}) film for diffusion barrier applications has been prepared by nitridation of a fine grain chemical vapor deposited tungsten (CVD-W) film. The fine grain CVD-W is deposited at 300{degree}C in a low pressure chemical vapor deposition reactor with a SiH{sub 4}/WF{sub 6} flow rate of 12.5/5 sccm under a total gas pressure of 100 mTorr. The subsequent nitridation process is executed in nitrogen plasma at 300{degree}C without breaking vacuum. The thickness of WN{sub x} layer as examined by secondary ion mass spectroscopy is 50 nm after 5 min exposure to nitrogen plasma. X-ray photoelectron spectroscopy spectra shows that the atomic ratio of tungsten to nitrogen in WN{sub x} layer is 2:1. According to the analysis by Auger electron spectroscopy and the measurement of n{sup +}p junction leakage current, the Al/WN{sub x}/W/Si multilayer maintains excellent interfacial stability after furnace annealing at 575{degree}C for 30 min. The effectiveness of W{sub 2}N barrier is attributed to stuffing grain boundaries with nitrogen atoms which eliminates the rapid diffusion paths in fine grain CVD-W films. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 496407
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 81; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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