TRIDYN Application Examples

1. Ion Doping
2. Redistribution of dopants
3. Sputter-controlled and saturable implantation profiles
4. Low-energy reactive ion sputtering of metals
5. Preferential sputtering of compounds
6. Ion-assisted deposition
7. Atomic mixing in multilayers
8. Sample contamination and damage during focused ion beam (FIB) erosion 


Ion doping

Foto: TRIDYN Ion Doping example ©Copyright: Prof. Dr. Wolfhard Möller

© W. Möller

800 keV Pr ion implantation at normal incidence into a  190 nm Si / 360 nm SiO2 double layer on Si for optical activation, at the fluences indicated. The injection of the dopant is accompanied by a significant broadening of the Si / SiO2 interfaces and sizeable surface sputtering, so that the Pr implantation peak is no longer in the centre of the oxide interlayer at the highest fluence.


Redistribution of Dopants

Foto: TRIDYN Redistribution of dopants example ©Copyright: Prof. Dr. Wolfhard Möller

© W. Möller Work supported by the European Union under Grant Agreement No. 688072 – IONS4SET

Ion irradiation processing may result in an undesired redistribution of dopants due to recoil atom transport. For a system similar to the one shown above, the top Si layer is doped with P at the indicated level. The original rectangular dopant distribution becomes blurred and extends significantly into the broadened and shifted O distribution. The example demonstrates that TRIDYN is able to handle atomic fractions down to ~10-6. (Work supported by the European Union under Grant Agreement No. 688072 – IONS4SET)


Sputter-controlled and saturable implantation profiles

Foto: TRIDYN Sputter-controlled example ©Copyright: Prof. Dr. Wolfhard Möller

© W. Möller

Foto: TRIDYN Sputter-controlled example 2 ©Copyright: Prof. Dr. Wolfhard Möller

© W. Möller

Total retention (a) and depth profiles (b) at increasing ion fluence during 10 keV S implantation into Mo at normal incidence. Re-sputtering of S results in a dynamic stationary state at sufficiently high fluence. In addition, it has been assumed that the local concentration of S is limited to the MoS2 stoichiometry, with excess S being re-emitted.


Low-energy reactive ion sputtering of metals

Foto: TRIDYN low-energy reactive ion sputtering example ©Copyright: P. Phadke

© P. Phadke (loc.cit.)

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High-fluence sputter yields during irradiation of selected metals with a mixture of N+ (20%) and N2+ (80%) ions delivered by a Kaufman ion source. For good agreement with the experimental results, the alteration of the surface binding energies due to nitrogen implantation has to be taken into account in the TRIDYN simulations. (from P. Phadke et al., Appl.Surf.Sci. 505(2020)144529)


Preferential sputtering of compounds

Foto: TRIDYN Preferential sputtering example ©Copyright: Prof. Dr. Wolfhard Möller

© W. Eckstein (loc.cit.)

Sputtering of TaC under low-energy He bombardment at normal incidence, in the limit of large fluence. Prefential sputtering of C due to the efficient collisional energy transfer from He to C depletes C at the surface and thus reduces the C sputtering yield at increasing fluence (inset). At continuous erosion, a stationary composition profile results at large fluence with the ratio of the elemental sputtering yields reflecting the bulk composition, as imposed by mass conservation. The simulation results agree well with experimental data, and allow to predict the sputtering yield at very low energy, where experiments failed. (From W. Eckstein and W. Möller, Nucl. Instrum. Meth. Phys. Res. B 7/8(1985)727)


Ion-assisted deposition

Foto: TRIDYN Ion-assisted deposition example ©Copyright: Prof. Dr. Wolfhard Möller

© D. Bouchier (loc.cit.)

Foto: TRIDYN Ion-assisted deposition example 2 ©Copyright: Prof. Dr. Wolfhard Möller

© W. Möller

Ion-assisted deposition of boron nitride on Ag by simultaneous delivery of thermal B from an evaporator and irradiation of 500 eV N from an ion source with the indicated geometry.  At an N/B flux ratio of 1:1, stationary growth is achieved at a total fluence around 1017 (N+B)/cm2 (left) with a B enrichment at the surface. The bulk N concentration stoichiometry is slightly above stoichiometric BN. The N/B bulk ratio resulting at varied N/B arrival ratio (right) is in good agreement with experimental results as long as it stays below stoichiometry. With a simple model of molecular reemission of N2 implemented in the code, good agreement is also obtained at higher fluences. (For details, see D. Bouchier and W. Möller, Surf. Coat. Technol. 51(1992)190 ) 


Atomic mixing in multilayers

Foto: TRIDYN atomic mixing example 1 ©Copyright: T. Prüfer

© W. Möller - work supported by the European Union under Grant Agreement No. 688072 – IONS4SET

Atomic mixing due to recoil atom transport at the interfaces of a 8 nm SiO2 interlayer in Si at a mean depth of 34 nm, under 50 keV Si bombardment at normal incidence and the fluences indicated. Substoichiometric SiOx is formed with a broadened O profile. The simultaneous shift of the profile results from sputtering and the additional Si atoms, which are mostly implanted behind the interlayer. The Si excess fraction denotes the Si atomic fraction in excess of the stoichiometric fraction 1/3. (See T. Prüfer et al., J. Appl. Phys. 125(2019)22;  work supported by the European Union under Grant Agreement No. 688072 – IONS4SET)

Foto: TRIDYN Atomic mixing example 2 ©Copyright: T. Prüfer

© W. Möller Download

Elemental depth profiles under 10 keV O irradiation of a magnetic Pt / MgO / FeB / Ta multilayer with thicknesses of 10 nm each on Si, at normal incidence and the fluences indicated.  The results demonstrate a complicated interplay of ion implantation, atomic mixing and surface erosion.


Sample contamination and damage during focused ion beam (FIB) erosion

Foto: TRIDYN Sample contamination example ©Copyright: J. Huang

© W. Möller Download

Ga contamination and sample damage during 30 keV Ga irradiation at a glancing angle of incidence of 83° with respect to the surface normal, at increasing ion fluence. (a) Ga depth profiles; (b) total amount of Ga; (c) depth profiles of damage assuming a displacement threshold energy of 20 eV; (d) depth of amorphization derived from (c), assuming and a critical damage level for amorphization of 0,16 dpa  (dpa = average nr. of displacements per target atom). Both Ga contamination and damage saturate at a fluence around 1016 ions/cm2. It must be noted that the TRIDYN simulation neglects thermal diffusion of Ga to the surface, which might influence the results in reality. (See also J. Huang et al., Ultramicroscopy 184(2018)52)


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Prof. Dr. Wolfhard Möller

w.moeller@hzdr.de
Phone: +49 351 260 2245


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