Abstract
A WF6-H2-N2 precursor system was used for plasma-enhanced chemical vapor deposition (PECVD) of WNx films. We examined the microstructural changes of the WNx films depending on N2/H2 flow-rate ratio and post-annealing (600-800 °C for 1 h). As the N2/H2 flow rate was increased from 0 to 1.5, as-deposited WNx films exhibited various different crystalline states, such as nanocrystalline and/or amorphous structure comprising W, WN, and W2N phases, a fine W2N granular structure embedded in an amorphous matrix, and a crystalline structure of β-W2N phase. After post-annealing above 600 °C, crystalline recovery with phase separation to β-W2N and α-W was observed from the WNx films deposited at an optimized deposition condition (flow-rate ratio = 0.25). From this PECVD method, an excellent step coverage of ∼90% was obtained from the WNx films at a contact diameter of 0.4 μm and an aspect ratio of 3.5.
Original language | English |
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Pages (from-to) | 426-433 |
Number of pages | 8 |
Journal | Current Applied Physics |
Volume | 7 |
Issue number | 4 |
DOIs | |
State | Published - May 2007 |
Keywords
- PECVD
- Phase
- Thin film
- WN