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DS: Fachverband Dünne Schichten
DS 15: Poster Session
DS 15.65: Poster
Dienstag, 27. März 2007, 15:00–17:00, Poster B
In-Situ Observation of Electron Stimulated Eching of SiO2 and the Initial Stage of Thermal Desorption — •Oliver Senftleben, Tanja Stimpel-Lindner, Ignaz Eisele, and Hermann Baumgärtner — Universität der Bundeswehr München, Institut für Physik, Werner-Heisenberg-Weg 39, 85577 Neubiberg
Thermal desorption of SiO2 under low oxygen partial pressure and elevated temperature due to the dissociation to SiO (g) is a well known process. Whereas electron irradiation causes dissociation of SiO2 to elemental silicon and oxygen that partly desorbs. Combining these two processes leads to a very effective way for etching of SiO2.
Therefore we investigated the etching effect on a thermally grown SiO2 with a thickness up to 60 nm at temperatures between 700∘ and 900∘C under electron irradiation in a UHV chamber. The etching process has been observed simultaneously via AES. The influence of temperature and carbon contaminations on the etching process can be shown.
We used this method to observe the initial stage of thermal desorption of SiO2. Therefore a hole 300 µm in diameter was etched into a 60 nm thick SiO2 layer right down to the silicon substrate which causes an inhomogeneity in SiO2 thickness in the transition region. The initial stage of thermal desorption of SiO2 can be observed very well utilizing this method.