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All issues Volume 5 / No 4-6 (August / October / December 1994) Microsc. Microanal. Microstruct., 5 4-6 (1994) 291-299 Abstract
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Issue
Microsc. Microanal. Microstruct.
Volume 5, Number 4-6, August / October / December 1994
Page(s) 291 - 299
DOI https://doi.org/10.1051/mmm:0199400504-6029100
Microsc. Microanal. Microstruct. 5, 291-299 (1994)
DOI: 10.1051/mmm:0199400504-6029100

Structure of Si(111) surfaces etched in 40% NH4F: Influence of the doping

J.R. Roche1, M. Ramonda1, F. Thibaudau1, Ph. Dumas1, Ph. Mathiez1, F. Salvan1 et P. Allongue2

1  Groupe de Physique des Etats Condensés, (URA CNRS 783), Faculté des Sciences de Luminy, 13288 Marseille Cedex 9, France
2  Laboratoire de Physique des Liquides et Electrochimie, UPR 15 CNRS, Université P. & M. Curie, 4 Place Jussieu, 75005 Paris, France


Abstract
The morphology of precisely oriented n and p+ type Si(111) hydrogenated surfaces has been studied by UHV-STM and AFM at ambient after "chemical" etching in 40% NH4F. Whereas atomically flat surfaces are obtained with the n-type samples, the surface of p+ substrates is rough. It is shown that these observations stem from a variation of the partition between the chemical (anisotropic) and the electrochemical (isotropic) components of the etching reaction. This is the uptake of the latter reaction path at the p+ -type specimen which explains the surface roughening in this case.


Résumé
La topographie de surface de plaquettes de Si(111) de type n et p +, orientées précisément, est étudiée par STM (dans le vide) et AFM (à l'air ambiant) après attaque "chimique" dans une solution de NH4F à 40 %. I1 apparait que le substrat de type n donne une surface plane à l'échelle atomique, et que la surface du substrat p+ est toujours rugueuse. On montre que ces observations résultent d'une augmentation de la composante électrochimique de la dissolution à la surface de type p+.

PACS
8165C - Surface cleaning, etching, patterning.
6835B - Structure of clean surfaces (reconstruction).

Key words
Experimental study -- Silicon -- N-type conductors -- P-type conductors -- Topography -- Surfaces -- Chemical etching -- Surface treatments -- Roughness -- Atomic force microscopy -- STM -- Ultrahigh vacuum -- Solid-fluid interfaces -- Liquid solid interface -- Band structure -- Reaction mechanism -- Surfaces -- Interfaces -- Condensed matter physics -- Materials science -- Physics -- Structure of liquids -- Structure of solids -- Crystallography -- Condensed state physics -- Nonmetals


© EDP Sciences 1994