Removal of the process‐induced fluorine associated to chemical vapor deposition of tungsten onto a polycrystalline silicon gate structure by heat treatment in a hydrogen‐containing atmosphere
| Autor: | François M. d'Heurle, Juhani Keinonen, C. S. Petersson, B. Mohadjeri, Th. Eriksson, Mikael Östling, Jens Carlsson |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Silicon
Inorganic chemistry General Physics and Astronomy chemistry.chemical_element Tungsten hexafluoride Chemical vapor deposition engineering.material Tungsten chemistry.chemical_compound Tungsten disilicide Polycrystalline silicon Hydrofluoric acid chemistry Etching (microfabrication) engineering |
| Zdroj: | Journal of Applied Physics. 68:2112-2120 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.346566 |
| Popis: | Tungsten was deposited from a gas mixture of hydrogen and tungsten hexafluoride onto a polycrystalline silicon gate structure in a chemical vapor deposition system. During the deposition process fluorine was also deposited as an undesired impurity. In order to remove the fluorine, heat treatments in the temperature range 550–1050 °C were performed in a hydrogen atmosphere. By this treatment it is possible to form volatile hydrofluoric acid and hence remove fluorine from the structure. Nuclear‐resonance‐broadening technique and secondary ion mass spectrometry were used for the analysis of fluorine. Fluorine was detected in all the samples except for the sample heat treated at 1050 °C. Moreover, etching of the polycrystalline silicon was observed. The gettering of fluorine, the etching of silicon and the observed formation of tungsten disilicide at 650 °C are discussed with respect to conceivable mechanisms. A thermodynamic study supporting the interpretations is also included. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|