Suppression of ion-implantation induced porosity in germanium by a silicon dioxide capping layer

Tran, Tuan T.; Alkhaldi, Huda; Gandhi, Hemi H.; Pastor, David; Huston, Larissa Q.; Wong‐Leung, Jennifer; Aziz, Michael J.; Williams, James S.

doi:10.1063/1.4961620

Cited by 21 publications

(22 citation statements)

References 25 publications

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“…However, for some ion species, porous structures or surface microstructural features have been observed in Ge even at LN 2 T. For example, Holland et al 14 detected blackening on the surface at a fluence of 3 Â 10 16 ions/cm 2 when implanting with 120 keV Sn þ ions, which is indicative of structural changes in Ge, but they did not show any TEM images of the microstructure. Similarly, recent work by Tran et al 2 observed porous structures by implanting 100 keV Sn þ ions with fluences between 2:5 Â 10 16 and 5 Â 10 16 ions/cm 2 for Sn þ at LN 2 T. This is consistent with the finding of Bruno et al, 16 who observed a honeycomb-like structure for antimony (Sb) implanted Ge at LN 2 T to a fluence of 6:4 Â 10 15 ions/cm 2 at 50 keV. Clearly, these reports show that for some heavy ion species, LN 2 T bombardment does not suppress porosity.…”

Section: Introductionmentioning

confidence: 65%

“…Doping Ge with high Sn concentration has also opened up applications for Ge-Sn photonics. 2 However, in all such applications that rely on ion implantation doping of Ge, the formation of a porous layer on the Ge surface is a significant issue and must be avoided or minimized. 3 For example, the formation of porosity in Ge has been reported to occur during ion implantation of crystalline Ge at room temperature (RT) at quite moderate implant fluences.…”

Section: Introductionmentioning

confidence: 99%

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The influence of capping layers on pore formation in Ge during ion implantation

Alkhaldi

Tran

Kremer

et al. 2016

Journal of Applied Physics

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Ion induced porosity in Ge has been investigated with and without a cap layer for two ion species, Ge and Sn, with respect to ion fluence and temperature. Results without a cap are consistent with a previous work in terms of an observed ion fluence and temperature dependence of porosity, but with a clear ion species effect where heavier Sn ions induce porosity at lower temperature (and fluence) than Ge. The effect of a cap layer is to suppress porosity for both Sn and Ge at lower temperatures but in different temperatures and fluence regimes. At room temperature, a cap does not suppress porosity and results in a more organised pore structure under conditions where sputtering of the underlying Ge does not occur. Finally, we observed an interesting effect in which a barrier layer of aGe that is denuded of pores formed directly below the cap layer. The thickness of this layer ($ 8 nm) is largely independent of ion species, fluence, temperature, and cap material, and we suggest that this is due to viscous flow of aGe under ion irradiation and wetting of the cap layer to minimize the interfacial free energy. Published by AIP Publishing.

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Section: Introductionmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

The influence of capping layers on pore formation in Ge during ion implantation

Alkhaldi

Tran

Kremer

et al. 2016

Journal of Applied Physics

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“…% Sn has been achieved using this method, with excellent crystal quality except for some local pore formation that occurs after ion implantation 7 . These defective regions have been shown to be a consequence of ion-beam induced porosity in Ge, which also increases the loss of Sn during implantation 8 . By using a nanometer scale pre-implantation capping layer of silicon dioxide (SiO2), the porosity and Sn loss due to sputtering are both significantly suppressed as shown in Ref.…”

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confidence: 99%

“…By using a nanometer scale pre-implantation capping layer of silicon dioxide (SiO2), the porosity and Sn loss due to sputtering are both significantly suppressed as shown in Ref. 8 . After implantation, a Sn content of ~15 .…”

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confidence: 99%

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Ion-beam synthesis and thermal stability of highly tin-concentrated germanium – tin alloys

Tran

Gandhi

Pastor

et al. 2017

Materials Science in Semiconductor Processing

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Native Oxide Layer Role during Cryogenic‐Temperature Ion Implantations in Germanium

Caudevilla,

Pérez‐Zenteno,

Duarte‐Cano

et al. 2024

Physica Status Solidi (a)

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Herein, the structural properties and chemical composition of Ge samples implanted with tellurium at cryogenic temperatures are analyzed, focusing on the role of the native oxide. For germanium, cryogenic‐temperature implantation is a requirement to achieve hyperdoped impurity concentrations while simultaneously preventing surface porosity. In this work, the critical role of the thin native germanium oxide is demonstrated when performing ion implantations at temperatures close to the liquid nitrogen temperature. The structural and chemical composition of tellurium‐implanted samples as a function of the implanted dose from 5 × 1014 to 5 × 1015 cm−2 is analyzed. After a laser melting process, the incorporated oxygen is diffused to the surface forming again a GeOx layer which retains a large fraction of the total implanted dose. These detrimental effects can be eliminated by a selective etching of the native oxide layer prior to the ion implantation process. These effects have been also observed when implanting on Si substrates. This work identifies key aspects for conducting implantations at cryogenic temperatures, that are otherwise negligible for ion implanting at room temperature.

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Suppression of ion-implantation induced porosity in germanium by a silicon dioxide capping layer

Cited by 21 publications

References 25 publications

The influence of capping layers on pore formation in Ge during ion implantation

The influence of capping layers on pore formation in Ge during ion implantation

Ion-beam synthesis and thermal stability of highly tin-concentrated germanium – tin alloys

Native Oxide Layer Role during Cryogenic‐Temperature Ion Implantations in Germanium

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