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Submitted on 1 Jan 1989
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ELECTRICAL ACTIVITY OF GRAIN BOUNDARIES IN SILICON BY THE S.T.E.B.I.C. METHOD
C. Cabanel, J.-Y. Laval
To cite this version:
C. Cabanel, J.-Y. Laval. ELECTRICAL ACTIVITY OF GRAIN BOUNDARIES IN SILICON BY THE S.T.E.B.I.C. METHOD. Journal de Physique Colloques, 1989, 50 (C6), pp.C6-154-C6-154.
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REVUE DE.PHYSIQUE APPLIQU~E
Colloque C6, Supplement au n 0 6 , Tome 24, Juin 1989
ELECTRICAL ACTIVITY OF GRAIN BOUNDARIES IN SILICON BY THE S.T.E.B.I.C.
METHOD
C. CABANEL a n d J.-Y. LAVAL
Laboratoire d e s Microstructures, CNRS-ESPCI, 10, r u e Vauquelin, F-75.231 Paris Cedex, France
In order to be able to analyse in TEM-STEM the crystallochemistry of recombining defects in p-type polysilicon (L = 100 pm), we have developed the scanning transmission electron beam induced current technique (STEBIC) originally proposed by Sparrow and Valdrex. The key point is the making of a thin Schottky diode which must be transparent to electrons. This is realized by means of an Al-Ga ohmic contact, ion milling and an A1 or Ag Schottky junction. Under such conditions an optimum lateral resolution of 190 nm is obtained and transmission imaging as well as diffraction , microdiffraction, X-ray microanalysis and EELS can be carried out concurrenty.
With this technique we have been able to correlate the segregation or precipitation of dopant such as A1 or impurities such as C and Ni to the electrical activity of grain boundaries. It seems that carbon has a tendency to trap oxygen at crystalline defects. The haloes displayed on fig. l,b around recombining areas correspond probably to oxygen diffusion towards dislocations (fig. 1,a) which creates a "clean" zone.
Fig.1: X3 boundary in polysilicon (a): localisation of the electrical activity at extrinsic dislocations by the S.T.E.B.I.C. technique (b).
From such results one sees that in order to understand the recombining processes at grain boundaries and structural defects a high spatial resolution is needed. This implies to have recourse to the STEBIC technique which should be of great value for developing new sophisticated heterostructures.
* SPARRUK T.G., and VALDRE U., Phil. Mag., 1977, 3_6 (6), 1517.
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1989614
