Numéro |
J. Phys. III France
Volume 3, Numéro 7, July 1993
|
|
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Page(s) | 1305 - 1312 | |
DOI | https://doi.org/10.1051/jp3:1993200 |
J. Phys. III France 3 (1993) 1305-1312
Mapping of dopant concentrations in photorefractive InP: Fe wafers
C. Ozkul1, M. A. Abdelghani-Idrissi1, S. Jamet1, P. Gravey2 and G. Picoli21 Université de Rouen, URA CNRS 230-CORIA, B.P. 118, 76134 Mont Saint Aignan Cedex, France
2 France TELECOM, CNET LA.B/OCM/TAC, Route de Trégastel, B.P. 40, 22301 Lannion Cedex, France
(Received 3 December 1992, accepted 16 February 1993)
Abstract
A photorefractive imaging technique, the principle of which is earlier described
by Bylsma et al. [1], is reconsidered. This technique allows an automatic
contactless characterization of semi-conductor substrates. Here, we are specifically
dealing with measurements of Fe concentrations in InP wafers. The Fe
2+ and Fe
3+
densities are deduced from the graph of the grating decay time constant as a function
of the read-out beam intensity by considering a single defect model and two
types of carriers. This model seems to be more adequate to describe the
experiments performed at large wavelengths such as
m.
We finally propose a modified photorefractive imaging geometry which uses
successively two gratings written at two different wavelengths. Although not
yet implemented, this geometry is based on the association of two types of measurements
that concern the decay time constants and the diffraction efficiencies resulting from
the photoexcitations at
m.
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