POSTIMPLANTATION EFFECTS ON 133[MATH]W

HAL Id: jpa-00219663

https://hal.archives-ouvertes.fr/jpa-00219663

Submitted on 1 Jan 1980

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

POSTIMPLANTATION EFFECTS ON 133[MATH]W

J. Odeurs, H. Pattyn, E. Verbiest

To cite this version:

J. Odeurs, H. Pattyn, E. Verbiest. POSTIMPLANTATION EFFECTS ON 133[MATH]W. Journal de

Physique Colloques, 1980, 41 (C1), pp.C1-449-C1-450. �10.1051/jphyscol:19801175�. �jpa-00219663�

JOURNAL DE PHYSIQUE Colloque C1, suppl6ment au n O 1 , Tome 41, janvier 1980, page C1-449

POSTIMPLANTATION

EFFECTS

J. Odeurs, H. Pattyn, E. Verbiest

I ~ x i t i t u u t voor Kern- en StraZingsfysika, Leuven University, B-3030 Leuven, Belgium.

1. INTRODUCTION

From the N6ssbauer Effect (ME) study of the annealing behaviour of 1 3 3 ~ e implanted in W it has become clear that Xe occupies several positions in the W-lattice: substitutional Xe occurs as well as Xe atoms associated with one or more vacancies.

Substitutional Xe in W (and in most other metals) acts as a strong vacancy trapper probably because it is largely oversized. The ME parameters carac- terising each Xe(Cs)-site are well known from reference 1. Therefore it is possible to study those physical processes for which the information has to be extracted from the site populations and their changes as a function of the implantation parameters (dose, dose rate, temperature, energy).

E.g. the measurements on the evolution of the site population as.? function of the annealing tempera- ture has proven to be useful for the study of the defect annealing stages in metals (for the vacancy annealing stage see ref.4, for interstitials see ref. 2).

In a recent series of measurements we were able to determine the position of the maximum of the vacancy distribution relative to the particle distribution that has produced them 3. For this purpose 1 3 3 ~ e has been implanted into each sample with a different energy. At the energy at which following the theory of Winterbon, Sigmund and Sanders 4 , maximum overlap occurs between the

"damage-profile" (produced by the 1 3 2 ~ e atoms) and the 1 3 3 ~ e distribution, we have found the largest decrease of the substitutional fraction.

With this postimplantation energy we have performed a series of measurements as a function of the 13'xe dose, which should provide information on the tran- sition between sites during the implantation.

2. EXPERIMENTAL RESULTS AND DISCUSSION.

1 3 3 ~ e has been implanted by means of the Leuven Isotope Separator into polycristalline W

(99.95% purity) at RT with an energy of 84 keV to a dose of 5.10 at/cm2. 13 A ME spectrum (the referen- ce spectrum) has been recorded with the source and

the absorber (480 mg/cm CsC1) at 4.2 K. Thereafter 2 stable 1 3 2 ~ e has been implanted into the 1 3 3 ~ e implanted W with an energy of 118 keV. The dose was

14 2 15

varied from 10 at/cm to 10 at/cm2. After each increase of the dose a ME spectrum has been recor- ded. Two spectra from this series together with the reference spectrum are displayed in fig. 1.

Fig.1. m-spectra of 133%2~. Reference spectmun together r ~ i t h two spectra recorded a f l e r postinpZantation of 1s2xe.

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19801175

(21-450 JOURNAL DE PHYSIQUE

All spectra are fitted with four different compo- nents (also drawn on thk figure) with a cornon linewidth From the analysis of the spectta the amplitude of every component (which is a measure af the population of that site) is known. We have calculated:

6 = - A1

4 (1)

C Aj j = 1

Ai is the amplitude of the j-th componerit of the reference spectrum. The different components come from the following site ideritikication site 1 is the substitutional site (notation XeV,), site 2 is a Xe atom to which one vacancy is associated (i(eVZ), site 3 a Xe-atom with two associated vacan- cies (XeV ) and site 4 a Xe-atom with three asso-

3

=iated vacancies (XeV4)

.

f

j;1

'

with the same meaning for the symbols as in equa- tion l , The index i stands for the i-th spectrum (after the i-th postimplantatiotl).

In figure 2 we have plotted 6i

' i =;T-

~ig.2. ?~oZution o f E; (eq.21 a s a function of the p o s t i ~ t a n t a t i o n I3'xe dose.

As can be seen from the figure, the population of the scbstiturional site decreases tjhen the post- implantation dose increases. During the implanta- tion there is a contihuous productioh of vacancies and interstitials. Tn W the Vacancies are immobile at RT while the idterstitials are already highly mobile

'.

the transition XeVI+XeV2 occurs when a vacancy, during the implantation, is produced within the trapping volume for single vacancies around a substitutional Xe-atom). The highly lhobile inter- sritials in turn will try to annihilate the vacan- cies before these are trapped by the Xe-impurities, thus reducing the trapping effect.

The almost linear decrease of the substitutio- nal fraction AS a function of the increasing post- implanted dose indicates that the probability, per incoming atom, for a substitutional atom to transit to vacancy-associated sites is constant

-

in the dose tange considered. This probability, as twadutad here, can then be used in the analysis of the dose dependence of the substitutional fraction in the normal case, i.e. where only radioactive atadls are implanted. The difference between these two dependences is to be attributed solely to the probability that an atom= substitutionally.

This then would allow us, by performing two series of measurements each with large enough activity, to deduce the landing probability, which figure can otherwise only be measured at very low doses

I I 2

( < l o at/cm ) and activities, and this makes such

measurements extremely difficult.

References.

J 1 / Reintsema, S.R., Verbiest, E., Odeurs, J.,

Pattyn, H., to be published in 3 . Phys.F (1979) /2/ Mansel, W., Meyer, H., Vogl, G . , Rad. Eff. 35,

( 1978) 69 and references therein

131 Pattyn, H., Odeurs, J., Verbiest, E., to be presented at the 8th Int. Conf. on Atomic Collisions in Solids, Hamilton 1979, (to be published in Nuol. fnstr. Meth.)

/4/ Winterbon, K.B., Sigmund, P., Sanders, J.B., Mat. Fys. Med. Dan. Vid. Selsk.37, (1970), 14 / 5 / Young, F.W., J. Nucl. Mat. 69 & 70, (1978) 310.

P Absolute sire populations cannot be computed because the recoilless fractions of the dif- ferent Xe sites in W are unknown.

cies increases, dan only occur when a vadancy is produced within the trapping volume for vacancies around a Xe-atom in a particular position (e.g.