Silicon consumption in excimer-laser-assisted chemical vapour deposition of tungsten

✍ Scribed by A.J.P. van Maaren; P.M. Zagwijn; W.C. Sinke

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 947 KB
• Volume: 8
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/0921-5107(91)90036-u

✦ Synopsis

We have deposited tungsten on silicon from WF 6 and H 2 by laser-assisted chemical vapour deposition. An ArF excimer laser was aligned parallel to the substrate. The deposition experiments were performed to investigate reactions between WF 6 and the silicon substrate. We investigated the roughness at the W-Si interface, caused by reactions between WF6, H2, and the substrate with Rutherford backscattering spectrometry (RBS) and high resolution cross-section scanning electron microscopy. The amount of silicon consumed during deposition was determined using RBS analysis in a marker experiment. The results show that the W-Si interface roughness decreases with increasing laser repetition frequency. The amount of reacted silicon decreases with increasing laser repetition frequency, for depositions on silicon both with and without a native oxide. Finally, a reaction mechanism for laser-assisted CVD of tungsten on silicon is presented which explains the observed phenomena. Atomic hydrogen, formed in the gas phase in an early stage of the deposition process, plays an important role in this reaction mechanism.