high-fluence co implantation in si, sio2/si and si3n4/si: part ii: sputtering yield transients, the...

High-¯uence Co implantation in Si, SiO2/Si and Si3N4/SiPart II: sputtering yield transients, the approach to high-¯uence

equilibrium

Yanwen Zhang a,*, Thomas Winzell a, Tonghe Zhang b, Ivan A. Maximov c,Eva-Lena Sarwe c, Mariusz Graczyk c, Lars Montelius c, Harry J. Whitlow a

a Department of Nuclear Physics, Lund Institute of Technology, Box 118, S-221 00 Lund, Swedenb Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875, People's Republic of China

c Department of Solid State Physics, Lund Institute of Technology, Box 118, S-221 00 Lund, Sweden

Received 25 March 1999; received in revised form 15 June 1999

Abstract

The partial sputtering yields of di�erent species from silicon dioxide/Si and silicon nitride/Si during high-¯uence keV

Co Metal Vapour Vacuum Arc (MEVVA) irradiation are of importance for both silicide formation and interpretation

of sputter pro®ling. Three sets of samples, nitride/Si(1 0 0), oxide/Si(1 0 0) and oxide/Si(1 1 1), have been bombarded to

di�erent normal ¯uences, H, from 1 ´ 1016 to 2.6 ´ 1018 ions cmÿ2. The partial sputtering yields for N and Si in the thick

nitride ®lms are �1.0 and �0.65, respectively, which indicates that the relative sputtering ratio of N/Si is �1.5. The

partial sputtering yields for O and Si of oxide/Si(1 0 0) samples are determined as �1.0 and �0.3, respectively. Although

the O and Si sputtering yields from oxide/Si(1 1 1) samples are �15% higher, the average sputtering ratio of O/Si is �3.4,

the same for both sets of oxide/Si samples. As expected, the partial sputtering yield of Co, YCo(H), is small for low

¯uence implantation and increases with increasing Co ¯uence. At a normal ¯uence of �5 ´ 1017 ions cmÿ2, YCo(H)

reaches the high ¯uence quasi-equilibrium limit, the value is very close to unity. The sputtering yield of Co reduces

slightly at even higher ¯uences, which is associated with erosion of the sample surface. Ó 1999 Elsevier Science B.V. All

rights reserved.

PACS: 79.20R; 68.55L; 68.35B; 85.40R

Keywords: Sputtering yield; Transients; High ¯uence equilibrium; ToF-E ERD; Silicon; Oxide; Nitride

1. Introduction

The changes in composition in the surfaceregion during high ¯uence keV-ion irradiation areimportant not only for silicide formation, theprimary aim of this study [1], but also for

Nuclear Instruments and Methods in Physics Research B 159 (1999) 133±141

www.elsevier.nl/locate/nimb

* Corresponding author: Present address: Division of Ion

Physics, �Angstr�om Laboratory, Box 534, Uppsala University,

S-751 21 Uppsala, Sweden. Tel.: +46-18-4713058; fax: +46-18-

555736; e-mail: [email protected]

0168-583X/99/$ - see front matter Ó 1999 Elsevier Science B.V. All rights reserved.

PII: S 0 1 6 8 - 5 8 3 X ( 9 9 ) 0 0 5 3 8 - 8

understanding the sputtering of compounds andatomic transport associated with recoil implanta-tion, ballistic ion-beam mixing and irradiationenhanced di�usion [2±6]. These processes are ofkey importance for the interpretation of data fromsputtering pro®ling measurements, such as Sec-ondary Ion Mass Spectrometry (SIMS), andsputter Auger pro®ling.

When a material consisting of more than oneelement is subjected to keV ion bombardment, theatoms of the material, as well as the implanted ionsmay be ejected from the surface by sputtering [7].Considering a target material made of n elements,the total sputtering yield [2], Y(H), at a normal¯uence H is

Y �H� �Xn�1

i�1

Yi�H�; �1�

where Yi(H) is the partial sputtering yield of ele-ment i integrated over all ejection energies andangles. The �n� 1�th element then corresponds tothe implanted species. Here the normal ¯uence His taken to be the time integral of the particlecurrent of ions crossing the surface plane [1]. Twotrivial limiting cases may be identi®ed [8]1. The low ¯uence limit with H� 0 where

Yn�1�0� � 0. i.e., no implanted atoms are sput-tered.

2. The high ¯uence quasi-equilibrium limit,Yn�1�1� � 1, where the loss of implanted atomsfrom the target by sputtering is counterbalancedto their rate of incorporation by implantation.In this case the maximum concentration Cmax

n�1

of the implant is [8]:

Cmaxn�1 �

1Pni�1 Yi�1� : �2�

The partial sputtering yields Yi(H) are governedby the sputtering probability Pi(x) and the con-centration Ci(x) of element i within the sputteringescape depth tescape through

Yi�H� �Z tescape

0

Ci�x� Pi�x� dx: �3�

Ci(x) will be modi®ed by Pi(x) acting in combi-nation with surface segregation during bombard-ment, transport by di�usion, and ballistic mixing

from depths greater than that one from whichsputtering ejection occurs. If the implanted ele-ment modi®es the chemical make-up of the target,e.g. through phase formation with one, or moretarget elements, this may in¯uence the partialsputtering yield by altering the transport of thatelement into the surface, even if this chemicalmodi®cation takes place below the sputteringejection depth. Furthermore, the situation iscomplicated because the Pi(x) values may dependon composition Ci(x) and may be changed by al-tered chemical driving forces [8,9].

The evolution of the partial sputtering yieldsfor high ¯uence Co implantation into Si, SiO2/Siand Si3N4/Si systems is interesting because Coreadily forms silicides (Co2Si, CoSi and CoSi2) aswell as oxides (CoO, Co2O3 and Co3O4) [10].Moreover, the behaviour of the Co±SiO2, Co±Siand Co±Si3N4 systems under ion irradiation is ofpractical importance for microelectronic technol-ogy.

Measurements of the partial sputtering yieldmay be made by analysis of the sputtered atom¯ux, either with a spectrometer, or by analysingmaterial collected on catcher foils. Another ap-proach is to measure the change in the surface andsubsurface composition. A third approach, whichwas employed here, is to measure the elementalcontents in the target. Here we have used Time-of-Flight Energy Elastic Recoil Detection (ToF-EERD) [11±15] to measure the retention of N, Oand Co in SiO2/Si and Si3N4/Si samples with dif-ferent oxide/nitride layer thicknesses. The workhere is the second part of a study on high ¯uenceCo implantation into Si, SiO2/Si and Si3N4/Si. The®rst part (Part I) focuses on the formation of thinsilicide surface ®lms [1] and Part III [16] deals withthe development of surface topography duringhigh ¯uence Co ion bombardment.

2. Experiment and method

Three sets of samples, nitride/Si(1 0 0), oxide/Si(1 0 0) and oxide/Si(1 1 1), have been bombardedwith Co in a ¯uence range from 1 ´ 1016 to2.6 ´ 1018 ions cmÿ2. The nitride and oxide layerswere obtained by Low-Pressure Chemical Vapour

134 Y. Zhang et al. / Nucl. Instr. and Meth. in Phys. Res. B 159 (1999) 133±141

Deposition (LPCVD) and dry oxidation, respec-tively [1]. The thicknesses of the surface layers,listed in Table 1, were measured by a micropro-cessor-controlled automatic-nulling ellipsometer[17]. The samples were analysed by ToF-E ERDusing 48 MeV 81Br8� ions as projectiles to measurethe total amount of N, O and Co, and the com-position of the surface layers. More detailed in-formation on sample preparation, implantationand ERD measurements, is given in Part I [1].

In this work we are primarily interested in thetotal amount of each element contained within thesurface layer which can be investigated by ERD.This was determined by comparing the totalnumber of the counts Ai in the signal from theelement i in question with the height HSi from a®xed energy interval DE of the Si signal at a depthdeep beneath the implanted region. By analogywith RBS analysis [18]

Ni �atoms=area�

� AN

HSi

gSi

gN

E0

Ea

ZSi

ZN

Mp �MSi

MP �Mi

� �� 2 DE

p�e�SiSi

: �4�

Here Ni is the coverage (i.e. the content per unitarea) of atoms of type i, gSi and gi the detectione�ciencies for Si recoils and recoils of type i, E0

the incident ion energy, Ea the energy prior toscattering from the deep Si layer, MSi, Mp and Mi

masses of Si, projectile ions and recoiled targetatoms of type i, DE the energy width spanning inthe deep Si layer, and p�e�Si

Si the stopping crosssection [19,20] factor for Si from the deep Si layer.

The absolute uncertainly is dominated by thecontributions from p�e�Si

Si and to a lesser degreefrom gSi and gi. However, the relative uncertainties

are only contributed from the much smallercounting statistical uncertainties in Ai and HSi.

3. Results and discussions

3.1. Nitrogen and oxygen contents of un-irradiated®lms

The relation of N or O content measured byElastic Recoil Detection (ERD) to the ®lm thick-ness measured by ellipsometry is shown in Fig. 1.The linear dependence of the O/N content on ®lmthickness indicates that the results from two mea-surements agree well with each other within themeasurement uncertainty. The refractive indexesof these ®lms are listed in Table 1. The values arevery close to 2 for all nitride ®lms and �1.49 foroxide ®lms with exceptions of the very thin ®lms.For the two thin ®lm samples (10 nm oxide/

Table 1

Thickness (t) and refractive index (n) determined by ellipsometry for the samples

Nitride/Si(1 0 0) Oxide/Si(1 0 0) Oxide/Si(1 1 1)

t (nm) n t (nm) n t (nm) n

145 2.04 144 1.47 142 1.47

72 2.01 70 1.49 69 1.49

37 2.02 34 1.53 35 1.53

13 2.04 10 1.71 11 1.71

Fig. 1. The total amount of N or O per unit area contained in

the sample from ERD measurement against the ®lm thickness

that measured from ellipsometry. The measurement uncertainty

of both ERD and ellipsometry are indicated as error bars in the

plot.

Y. Zhang et al. / Nucl. Instr. and Meth. in Phys. Res. B 159 (1999) 133±141 135

Si(1 0 0) and 11 nm oxide/Si(1 1 1) samples), therefractive index is 1.71, which is larger than 1.46,the index of SiO2 thermally grown at 1000°C [21].This may imply that these two thin ®lms have notbeen oxidised completely to stoichiometry, andthere might be a mixture of SiO2, SiO and Si. It isnotable that the ®tted lines in Fig. 1 do not passthrough zero. We believe that this is associatedwith uncertainties of the two methods. For theERD measurements, the absolute uncertainty isdominated by the �10% stopping power uncer-tainty. The ellipsometer errors are more di�cult toestimate because of the non-stoichiometry at theinterface and contamination at the surface, whichmodi®es the refractive index. These are more sig-ni®cant for thinner oxide ®lms.

Fig. 2 presents the measured N/Si and O/Siatomic ratio versus depth for the 145 nm nitride/Si(1 0 0), 144 nm oxide/Si(1 0 0) and 142 nm oxide/

Si(1 1 1) samples, respectively. The error bars de-note the relative measurement uncertainties; theabsolute systematic stopping power uncertainty isnot included. The dashed lines indicate the stoic-hiometric compositions. Clearly, the thick nitrideand oxide ®lms have N/Si and O/Si ratios that arein good agreement with the stoichiometric valuefor Si3N4 and SiO2. This is commensurate with theobservation of the measured refractive index forthese ®lms (Table 1).

The normalised ERD energy spectra of N, Oand Si from the three sets of samples are shown inFig. 3 after the proper mass gates have been ap-plied. Inspection of the normalised N spectra (Fig.3A) from the un-irradiated nitride/Si samples,shows that the widths of the N signal increase withincreasing thickness, and the heights are closelysimilar except for the thinnest nitride ®lm (13 nm).A step with the same surface height appears in the

Fig. 2. Atomic ratio of N/Si or O/Si for thick ®lm samples. The

error bars represent the relative uncertainties. The uncertainty

of stopping power (�10%) which should be concerned as a

systemic uncertainty is not included.

Fig. 3. The normalised energy spectra of N, O and Si for nit-

ride/Si(1 0 0) samples (A and a), oxide/Si(1 0 0) samples (B and

b), and oxide/Si(1 1 1) samples (C and c).


Si spectra (Fig. 3a) for 37, 72 and 145 nm ®lms.The spectrum height of N for the 13 nm ®lmsample is much lower than the other samples (Fig.3A) and there is no clear plateau that can be dis-cerned in this sample (Fig. 3a). This can be at-tributed to the ®nite depth resolution (�20 nmFWHM) being greater or comparable to thethickness of the ®lm. From the data in Figs. 2(a)and 3 (a and A) we can conclude that the com-position of the thicker ®lms is in good agreementwith Si3N4. The spectra for the two sets of oxidesamples (Fig. 3B±c) show similar behaviour.Comparison with the ellipsometry data (Table 1)shows that where the ®lm is stoichiometric, therefractive index is in good agreement with the bulkvalues, �2.00 and �1.46 for Si3N4 and SiO2, re-spectively [21,22]. Although the refractive index ofthe nitride samples is constant even for the thin-nest ®lms, the refractive index of the oxide ®lmsbecomes larger as the ®lm thickness decreases.

3.2. Partial sputtering yield

Fig. 4 presents the 14N and 16O contents re-tained in the samples, N0(H) and NN(H), respec-tively, versus Co normal ¯uence H. The data forall ®lms indicate a close-to-linear decrease towardszero. As the ®lm thickness increases the ¯uencerequired reducing the O and N contents to zeroincreases as one might expect. The average partialsputtering yield �Yi, which is the slope of the lines, isgiven in Table 2. The ®tted initial O and N con-tents are corresponding to the zero-¯uence inter-cept. YN for the Si3N4/Si(1 0 0) and YO for the SiO2/Si(1 0 0) samples show a noticeable decrease forthinner ®lms whilst YO for the SiO2/Si(1 11) sam-ples is constant within the limits of counting sta-tistical uncertainties.

The reduction of partial sputtering yields withdecreasing ®lm thickness is seen more clearly in the¯uence dependence of the N and O partial sput-tering yields, Yi�H� � DNi�H�DH, shown in Fig. 5.As one might expect, the partial sputtering yieldsvanishes in the limit that the O and N contentsbecome zero. It may also be seen that YN�H� andYO�H� are systematically greater for the thicker(�145 nm) ®lms. Assuming the extreme conditionthat all the ions from the MEVVA source are

Co2�, SRIM [19,20] estimates of the range for 30°o�-normal incidence are 67.9, 65.4 and 54.5 nm inSi3N4, SiO2 and Si, respectively. In the case of thethinner ®lms (�35 and 70 nm), the ions will pen-etrate to depths near the interface. Thus for thethinner ®lms there may be considerable interfacialmixing by the ion beam leading to a reduction ofO and N at the surface. This would produce apersistent tail on a plot of NN�H� versus H andNO�H� versus H. Unfortunately, the ¯uence-stepused here is too wide to allow any ®rm conclusionsto be drawn about this. Plots of Yi�H� versus Ni�H�for the nitride and oxide ®lms indicate that therewas a correlation between Yi�H� and Ni�H�, Yi�H�was systematically greater for the ®lms that

Fig. 4. The retention of O and N versus Co normal ¯uence for:

(a) Si3N4/Si(1 0 0) samples, (b) SiO2/Si(1 0 0) samples and (c)

SiO2/Si(1 1 1) samples.


were initially thick. This is supporting, but notconclusive evidence that mixing of the interfacecontributes to the reduction of the partial sput-tering yield.

The retention of Si in the thick oxide andnitride ®lms (�145 nm) NSi(H) is presented inFig. 6. The estimate of NSi(H) is based on the

change in the area of the Si signal extending fromthe surface to a depth corresponding to the ®tted

Fig. 6. Si retention versus Co normal ¯uence for: (a) 145 nm

Si3N4/Si(1 0 0) sample, (b) 144 nm SiO2/Si(1 0 0) sample and (c)

142 nm SiO2/Si(1 1 1) sample.

Fig. 5. Partial sputtering yield of O and N versus average Co

normal ¯uence for: (a) Si3N4/Si(1 0 0) samples, (b) SiO2/Si(1 0 0)

samples and (c) SiO2/Si(1 1 1) samples.

Table 2

The average partial sputtering yields of O, N and Si, and average ratio of N/Si and O/Si

Average partial sputtering yield Si3N4/Si(1 0 0) SiO2/Si(1 0 0) SiO2/Si(1 1 1)

Slope Intercept Slope Intercept Slope Intercept

YN or YO (144±142 nm) ÿ1.084 6.83 ´ 1017 ÿ1.193 6.41 ´ 1017 ÿ1.137 6.15 ´ 1017

YN or YO (69±72 nm) ÿ0.951 3.19 ´ 1017 ÿ0.859 2.66 ´ 1017 ÿ1.2637 2.43 ´ 1017

YN (37 nm) ÿ0.792 1.60 ´ 1017 ÿ ÿ ÿ ÿYSi (144±142 nm) ÿ0.648 6.07 ´ 1017 ÿ0.319 3.71 ´ 1017 ÿ0.349 3.65 ´ 1017

Average Yi=YSi �1.5 �3.4 �3.4


half-height position of the step in the Si ERDsignal (see e.g. Fig. 3). We emphasise that thismeasurement of Si in the ®lm cannot distinguishbetween the e�ect of Si lost from the surface bysputtering and Si atoms moving into or out of thesilicide/silicon interface. The straight-line behav-iour seen in Fig. 6 supports the argument abovethat the ®lm is progressively eroded. The slopes ofthe lines correspond to the average partial sput-tering yield of Si YSi in the coating ®lms, while theintercept Nsi(0) is the ®tted initial Si contents in theun-irradiated nitride or oxide ®lms. The ratio�Yi=�YSi of the average partial sputtering yields is�1.5 and �3.4 for the thicker nitride and oxidesamples, respectively. Although in all cases the lossof N or O is over stoichiometric, it is much closerto the stoichiometric value for nitrides ®lms (1.33)than for oxide ®lms (2.00). These values might beassociated with the transport of Si from the sub-strate into the ®lm (noted above) or the partialsputtering yield for Si is reduced because Si isbound by formation of silicide(s). If the latter istrue, it implies that silicides are formed more easilyin oxide than in the nitride layers.

Fig. 7 presents the partial sputtering yield forCo, YCo�H� � DNCo�H�=DH is the net increase ofthe Co content in the samples with the increase ofimplanted Co normal ¯uence, DH. In the highnormal ¯uence limit 5 ´ 1017 ions cmÿ2, YCo�H�approaches the asymptotic expectation value ofunity. The deviation can be attributed to uncer-tainties in the ¯uence measurements associatedwith assumption of an average charge state andthe stopping cross-section factor Br�e�Si

Si associatedwith the stopping power. Furthermore, the ap-proach of the quasi-equilibrium may be delayed bychanges in the surface morphology discussed be-low.

Considering ®rst the behaviour for the sampleswithout oxide or nitride ®lms it is seen that evenfor a mean normal ¯uence of 5 ´ 1015 ions cmÿ2 thepartial YCo is �0.5. SRIM [19,20] estimates of theCo depth distribution in the zero-¯uence limitsuggest that at this ¯uence the Co concentrationwithin 10 nm of the surface should be less than 2.6and 0.62 at.% for 40 keV 59Co� and 80 keV59Co2�ions, respectively. The implication is thatthere must be both a signi®cant mobility and a

driving force that e�ciently transports Co into thesputter escape depth. Fig. 7 also shows that theasymptotic levels for Si without oxide or nitride®lms are considerably smaller than 1. This is mostnoticeable in the case of Si(1 0 0) where YCo in-creases rapidly up to an average normal ¯uence of1.5 ´ 1017 Co ions cmÿ2 and then increases slowly.This may be associated with the growth of thecolumnar structure [16], which begins with theformation of pores at normal ¯uences around5 ´ 1017 Co ions cmÿ2. The di�erence in Co reten-tion is then associated with the dependence ofmorphological growth on surface orientation. Thisis possible if the development of a rough surfacetopography provides a route for Co to penetratedeep into the bulk, although this cannot preventthe quasi-equilibrium from being ultimatelyreached. For Co normal ¯uences in excess of

Fig. 7. The partial sputtering yield of Co versus average Co

normal ¯uence for: (a) nitride/Si(1 0 0) samples, (b) oxide/

Si(1 0 0) samples and (c) oxide/Si(1 0 0) samples.


1018 ions cmÿ2 the ¯at topography transforms to aforest of acicular needles [15]. If the rate of deepCo penetration is larger compared to the rate ofCo loss by sputtering, the Co retention fractionmay increase as a result of the change in surfacetopography. This, in turn, would manifest itself asa reduction of YCo�H� which may account for thescatter in the high normal ¯uence data points inFig. 7. It might be worth noting that the e�ect ofchannelling is unlikely to be a possible explanationof the slower approach to the asymptotic level forSi(1 0 0) and Si(1 1 1) as the Co ¯uence is su�cientto make the layer amorphous.

Fig. 7 shows that both nitride and oxide ®lmsmodify the transient in the Co partial sputteringyield and the asymptotic saturation value isreached somewhat faster for the thicker ®lms.Close inspection of Fig. 7 shows that the asymp-totic value is closer to one than that for the bare Sitargets without ®lms. Moreover, the initial rate ofapproach is greatest for the thicker ®lms. This isbecause the oxide and nitride ®lms delay the onsetof the transition to a rough surface topography[15], which leads to a more complete and rapidattainment of the asymptotic value for YCo�1�.This is commensurate with surface rougheningproviding an e�cient route to incorporate Co intothe bulk. In all cases an average normal ¯uence of�5 ´ 1017 Co ions cmÿ2 is needed to attain theasymptotic value within 10%. This corresponds toremoval of a layer with thickness �100±150 nm bysputter erosion roughly twice the projected range.This places a limit on the maximum thickness ofsilicide that can be formed by high ¯uence Co ionimplantation. Touboltsev et al. [23] have reporteda similar modi®cation of the sputtering transientand an initially enhanced In concentration for In�

implantation into Al(1 1 0) which they attribute tothe presence of a thin surface oxide during theinitial stages of irradiation.

4. Conclusions

1. The number of oxygen and nitrogen atoms inSi3N4 and SiO2 ®lms on Si determined byToF-E ERD shows a linear dependence on thethickness measured by ellipsometry. The

composition of thick ®lms measured withToF-E ERD is in agreement with the stoic-hiometric value within the limits of systematicuncertainty.

2. The decrease in oxygen and nitrogen retentionin the oxide and nitride ®lms closely follows alinear dependence on Co ¯uence. In the caseof the thick ®lms (�145 nm), where there is awell-developed step in the Si signal at the inter-face between the oxide/nitride ®lm and the Sibulk, the Si content of the ®lm also follows alinear dependence on the Co ¯uences. The ratios�YN=�YSi and �YO=�YSi of the average partial sputter-ing yields exceed the stoichiometric value.

3. The initial partial sputtering yields for oxygenand nitrogen are greater for thicker oxide andnitride ®lms. The partial sputtering yields be-come zero in the high ¯uence limit where the®lm has been eroded away.

4. In all the samples investigated, a Co partialsputtering yield of �0.5 is reached after an aver-age normal ¯uence of 5 ´ 1015 Co ions cmÿ2,suggesting that Co is e�ciently transported tothe surface of the sample where it is sputterejected. The partial sputtering yield for Co ap-proaches the asymptotic value close to unity.The transient extends to a Co normal ¯uenceof �5 ´ 1017 Co ions cmÿ2. The deviations fromthe asymptotic value may be associated with thedevelopment of a rough surface topography.

Acknowledgements

We are grateful to the sta� at the Tandem Ac-celerator Laboratory in Uppsala and the Instituteof Low Energy Nuclear Physics, Beijing NormalUniversity for help and assistance. This investiga-tion has been carried out under the auspices of theNFR/NUTEK Nanometer Structure Consortium.

References

[1] Y. Zhang, T. Winzell, T. Zhang, M. Andersson, I.A.

Maximov, E.-L. Sarwe, M. Graczyk, L. Montelius, H.J.

Whitlow, this issue, Nucl. Instr. and Meth. B 159 (1999)

142.


[2] P. Sigmund, A. Grass-Marti, Nucl. Instr. and Meth. 182/

183 (1981) 25.

[3] P. Sigmund, A. Oliva, G. Falcone, Nucl. Instr. and Meth.

194 (1982) 541.

[4] H.H. Andersen, Appl. Phys. 18 (1979) 131.

[5] P. Sigmund, Phys. Rev. 184 (1969) 383.

[6] G. Betz, G.K. Wehner, in: R. Behrisch (Ed.), Topics in

Applied Physics, vol. 52, Sputtering by Particle Bombard-

ment II, Springer, Berlin, 1983.

[7] P. Sigmund, in: R. Behrisch (Ed.), Topics in Applied

Physics, vol. 47, Sputtering by Particle Bombardment I,

Springer, Berlin, 1981.

[8] H.H. Andersen, in: J.S. Williams, J.M. Poate (Eds.), Ion

Implantation and Beam Processing, Academic Press,

Australia, 1984, p. 127.

[9] H.H. Andersen, B. Stenum, T. Sùrensen, H.J. Whitlow,

Nucl. Instr. and Meth. 210 (1983) 487.

[10] T.B. Massalski, Binary Alloy Phase Diagrams, American

Society for Metals, Metals Park, Ohio, 1986.

[11] H.J. Whitlow, A.B.C. Andersson, C.S. Petersson, Nucl.

Instr. and Meth. B 36 (1989) 53.

[12] H.J. Whitlow, B. Jakobsson, L. Westerberg, Nucl. Instr.

and Meth. A 310 (1991) 636.

[13] H.J. Whitlow, M. Andersson, M. Hult, L. Persson, M. El

Bouanani, M. �Ostling, C. Zaring, N. Lundberg, D. Cohen,

N. Dytlewski, P.N. Johnston, I.F. Bubb, S.R. Walker, E.

Johanson, S. Hogmark, P.A. Ingemarsson, Mikrochim.

Acta. 120 (1995) 171.

[14] M. Hult, H.J. Whitlow, M. �Ostling, M. Andersson, Y.

Andersson, I. Lindeberg, K. St�ahl, J. Appl. Phys. 75 (1994)

835.

[15] M. El Bouanani, M. Hult, L. Persson, E. Swietlicki, M.

Andersson, M. �Ostling, N. Lundberg, C. Zaring, D.D.

Cohen, N. Dytlewski, P.N. Johnston, S.R. Walker, I.F.

Bubb, H.J. Whitlow, Nucl. Instr. and Meth. B 94 (1994)

530.

[16] Y. Zhang, T. Winzell, T. Zhang, I.A. Maximov, E.-L.

Sarwe, M. Graczyk, L. Montelius, H.J. Whitlow, this

issue, Nucl. Instr. and Meth. B 159 (1999) 158.

[17] Auto EL-II Automatic Ellipsometer Instruction Manual,

Rudolph Research, 1980.

[18] W.-K. Chu, J.W. Mayer, M.-A. Nicolet, Backscattering

Spectrometry, Academic Press, New York, San Francisco,

London, 1978.

[19] J.F. Ziegler, SRIM-2000 Instruction Manual, 1998.

[20] J.F. Ziegler, J.P. Biersack, U. Littmark, The Stopping and

Range of Ions in Solids, vol. I, Pergamon, New York,

1985; See also J.F. Ziegler, TRIM Instruction Manual,

1997.

[21] S.M. Sze, Semiconductor devices, Physics and Technology,

Wiley, New York, 1985, p. 357.

[22] D.B.E. Flemns, P.J. Castro, J. Electro. Soc. 75 (1968)

300.

[23] V.S. Touboltsev, G. Dybkjñr, A. Johansen, E. Johnson,

L. Sarholt, H.H. Andersen, M. Olsen, Phil. Mag. A 77

(1998) 341.


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