Oxygen '96
Early Stages of Oxygen Precipitation in Silicon
LOW TEMPERATURE ANNEALING STUDIES OF THE DIVACANCY IN P-TYPE
SILICON
J. Vanhellemont
(a),
M.-A. Trauwaert (a),
A.-M. Van Bavel (b), P. Clauws (c), A. Stesmans (b),
H. E. Maes (a) and G. Langouche (b)
(a) IMEC, Kapeldreef 75, B-3001 Leuven, BELGIUM
(b) KUL, Celestifnenlaan 200D, B-3001 Leuven, BELGIUM
(c) RUG, Krijgslaan 281-S1, B-9000 Gent, BELGIUM
Keywords: divacancy, low temperature anneal, DLTS, oxygen,
silicon.
The divacancy is easily created in silicon by irradiation with high
energy electrons and has therefore been studied more than thirty years
by a wide variety of techniques. Deep level transient spectroscopy
analyses of irradiated p-type silicon in the literature makes the link
between the divacancy and a majority carrier trap with reported energy
levels between Ev + 0.19 and Ev + 0.24 eV.
In the present study the Ev + 0.19 eV deep level is also
observed after irradiation at room temperature. After prolonged
anneals at temperatures between 200 and 300 degrees C a gradual shift
of the deep level with annealing time occurs however towards
Ev + 0.24 eV [1]. The observed transition is much faster in
Cz than in FZ silicon suggesting the involvement of oxygen
(Fig. 1). It is shown that this apparent gradual shift of the deep
level in the bandgap can be explained by a gradual transformation of
the divacancy with trap parameters (Ev + 0.17 eV, capture
cross-section sigma ~ 10-17 cm-2) towards
another defect with trap parameters (Ev + 0.24 eV, sigma ~
10-15 cm-2). The final defect is assumed to be a
multi-vacancy / oxygen complex. First results will also be presented
of an electron spin resonance and infrared spectroscopy study before
and after the transition to corroborate this hypothesis.
Fig. 1: Left:
Typical DLTS spectra before (full line) and after (dotted line) a 10
day anneal at 200 degrees C of a 2 MeV electron irradiated p-type Cz
substrate. Right: Kinetics of the apparent deep level energy shift for
different anneal temperatures.
[1]. M.-A. Trauwaert,
J. Vanhellemont, H. E. Maes, A.-M. Van Bavel, G. Langouche and
P. Clauws, Appl. Phys. Lett. 66, 3057 (1995).
J. Vanhellemont's next
abstract | full list of abstracts |
participants
list | main page.
Last modified: Mon Feb 19 12:10:49 GMT 1996
JG
