Seminars Archive
Pavo Dubcek
Abstract
Thursday, March 22, 2001, 16:00
Seminar Room, ground floor, Building "T"
Sincrotrone Trieste, Basovizza
Structural changes in annealed, hydrogen implanted monocrystalline silicon.
Pavo Dubcek
(Sincrotrone Trieste)
ABSTRACT
The grazing incidence small angle X-ray scattering (GISAXS) technique
was used to investigate monocrystalline silicon samples implanted with
hydrogen and annealed isochronally at different temperatures in the range
from 100oC to 900oC.
Although the hydrogen depth distribution was expected to be smooth
initially, nanosized features, like agglomerates of defects, have been
detected in the implanted sample. After annealing this features are destroyed
due to the relaxing of the defect structure, controlled by hydrogen captured
in intersticials, as well as in produced vacancies. Above 300 oC a well
defined film with highly correlated borders is formed on the edge of the
layer rich in defects (presumably due to the migration of vacancies and
hydrogen), whose thickness is slowly decreasing with increasing annealing
temperature. This is attributed to vacancies and bubbles agglomeration,
and the size decreases due to hydrogen abandoning the vacancies in the
region. With increasing annealing temperature, defects as well as hydrogen
are migrating towards the surface, as it is indicated by the increase of
the surface roughness. A model for the film structure changes is constructed
after data evaluation using distorted wave Born approximation.
