Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 22: Epitaxie und Wachstum I
O 22.13: Vortrag
Dienstag, 25. März 2003, 18:00–18:15, FOE/ORG
Structural quality of ultra-thin silicon nitride films — •T. Clausen1, Th. Schmidt1, S. Gangopadhyay1, J. Falta1, S. Heun2, L. Gregoratti2, M. Kiskinova2, and S. Bernstorff2 — 1Institute of Solid State Physics, University of Bremen, Postbox 330440, 28334 Bremen — 2Elettra Synchrotron Light Source, Strada Statale 14, 34012 Basovizza, Trieste, Italy
Due to a higher dielectric constant silicon nitride films are
interesting as isolation layers replacing SiO2 in the ongoing
miniaturization of silicon device technology. Moreover Si3N4
films could serve as buffer layers for GaN growth on silicon
substrates in integrated optoelectronics. Both aims require films with
high quality.
We have investigated the structural quality of
ultra-thin silicon nitride films on Si(111) substrates - prepared by
reactive ECR plasma source deposition - regarding their morphology and
chemical stoichiometry using atomic force microscopy (AFM), scanning
tunneling microscopy (STM), x-ray reflectivity (XRR), low energy
electron diffraction (LEED) and scanning photoelectron microscopy
(SPEM).
The experiments show that the morphology of the silicon
nitride films strongly depends on the nitridation temperature. At low
temperature deposition from 700∘C to 800∘C
atomically flat silicon nitride films have been observed, which show a
stoichiometry in agreement with Si3N4. High temperature
deposition from 935∘C to 1000∘C leads to pronounced
grooves and holes in the film of up to 1 µm diameter and
depths in the range of the film thickness. Nevertheless SPEM
measurements indicate the growth of silicon nitride also inside these
holes.