Investigation of chemically vapour deposited tungsten and tungsten silicide as contacts to n+ and p+ silicon areas
1990 (English)In: Thin Solid Films, ISSN 00406090 (ISSN), Vol. 185, no 1, 9-19 p.Article in journal (Refereed) Published
Tungsten and WSi2 have been examined as contact barriers between aluminium and n+ - or p+ -Si. The specific contact resistivity and diode leakage current were evaluated after heat treatment at different temperatures. Rutherford backscattering spectrometry measurements, X-ray diffraction analysis, scanning electron microscopy and sheet resistance measurements were performed to study the thermal stabilities of the Al/W/Si and Al/WSi2/Si systems. The contact resistivities of chemically vapour deposited tungsten and WSi2 to n+ -Si with a surface concentration of 7.5 Ã— 1019 cm-3 were 8 Ã— 10-7 Î©cm2 and 9 Ã— 10-7 Î©cm2 respectively. To p+ -Si with a surface concentration of 2.6 Ã— 1019 cm-3, they were 5 Ã— 10-6 and 1 Ã— 10-6 Î©cm2. Diffusion of aluminium was revealed to occur above 475Â°C in the case of tungsten and at 475Â°C in the case of WSi2. The void formation in silicon substrates was observed after heat treatment at 500Â°C for the Al/WSi2/Si system. The increase in leakage current for the Al/W/Si and Al/WSi2/Si structures is related to the onset of Si-Al interpenetration. Alloy formation was observed at 500Â°C for tungsten contacts whereas W-Al or other alloys were not detected up to 600Â°C for the WSi2 contact. Â© 1990.
Place, publisher, year, edition, pages
1990. Vol. 185, no 1, 9-19 p.
Aluminum and Alloys--Diffusion, Integrated Circuits, VLSI, Semiconducting Silicon--Contacts, X-rays--Diffraction, Rutherford Backscattering Spectrometry, Tungsten Silicide, Tungsten and Alloys
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:kth:diva-83051OAI: oai:DiVA.org:kth-83051DiVA: diva2:498651
Correspondence Address: Hammar, M.; Swedish Institute of Microelectronics, P.O. Box 1084, S-16421 Kista, Sweden NR 201408052012-02-122012-02-122012-02-12Bibliographically approved