Chlorine Etching for In-Situ Low-Temperature Silicon Surface Cleaning for Epitaxy Applications

Chung, Keith; Sturm, James C.

doi:10.1149/1.2727426

Cited by 8 publications

(5 citation statements)

References 4 publications

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“…Although Cl 2 is widely studied and applied in ion reactive etching [1,2], its use for group IV epitaxy has been relatively limited, despite opening great opportunities for the development of low temperature selective epitaxial processes. Only a few existing reports point to the several etching experiments on crystalline Si by K Chung et al [3] and some fragmented data on etching of crystalline and amorphous Si by M Bauer et al [4,5]. Even though these preliminary data are very promising, and helped to develop an advanced cyclic processes for selective deposition of Si:C:P epitaxial layers, the overall picture with a Cl 2 etch of group IV materials is far from being complete.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Cl₂etch in view of extremely low temperature selective epitaxial processes

Hikavyy

Kruv

Opstal

et al. 2017

Semicond. Sci. Technol.

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A Cl 2 etch of different group IV materials in a low temperature range (260-600 °C) is presented. It is shown that in general the Cl 2 etching behavior is very similar to that of HCl: Si is etched slowest, Ge fastest with SiGe being between these two cases. Activation energies for Cl 2 etching of Si, SiGe and Ge are very low and show that neither Cl nor H surface passivation are limiting factors for the etch. The etching rate is strongly affected by the choice of the carrier gas (He, H 2 and N 2 ) and by the process pressure which gives high flexibility for its application. As compared to HCl, Cl 2 allows decreasing of the etching process temperatures down to ∼400 °C for Si and ∼250 °C for Ge. Although it is not clear if co-flow selective processes are visible due to possible exothermic chain reaction of radicals in the presence of group IV hydrides, cyclic approaches can be relatively easily achieved at temperatures below 500 °C.

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Section: Introductionmentioning

confidence: 99%

Investigation of Cl₂etch in view of extremely low temperature selective epitaxial processes

Hikavyy

Kruv

Opstal

et al. 2017

Semicond. Sci. Technol.

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“…The pH was adjusted by adding HCl or KOH. At room temperature, the etch rate of SiO 2 at these pH values is ≪1 nm h –1 , and thus no impact on the size or shape of the pores is expected. , Using Ag/AgCl electrodes on either side of the membrane, we measured the current–voltage ( I – V ) characteristics of the pores between −1 and 1 V to determine the membrane conductance and ion current rectification (ICR). The setup is described in more detail in the Supporting Information (Figure S8).…”

Section: Resultsmentioning

confidence: 99%

Highly Rectifying Conical Nanopores in Amorphous SiO₂ Membranes for Nanofluidic Osmotic Power Generation and Electroosmotic Pumps

Kiy

Dutt

Notthoff

et al. 2023

ACS Appl. Nano Mater.

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Nanopore membranes are a versatile platform for a wide range of applications ranging from medical sensing to filtration and clean energy generation. To attain high-flux rectifying ionic flow, it is required to produce short channels exhibiting asymmetric surface charge distributions. This work reports on a system of track etched conical nanopores in amorphous SiO2 membranes, fabricated using the scalable track etch technique. Pores are fabricated by irradiation of 920 ± 5 nm thick SiO2 windows with 2.2 GeV 197Au ions and subsequent chemical etching. Structural characterization is performed using atomic force microscopy, scanning electron microscopy, small-angle X-ray scattering, ellipsometry, and surface profiling. Conductometric characterization of the pore surface is performed using a membrane containing 16 pores, including an in-depth analysis of ionic transport characteristics. The pores have a tip radius of 5.7 ± 0.1 nm, a half-cone angle of 12.6 ± 0.1°, and a length of 710 ± 5 nm. The pK a, pK b, and pI are determined to 7.6 ± 0.1, 1.5 ± 0.2, and 4.5 ± 0.1, respectively, enabling the fine-tuning of the surface charge density between +100 and −300 mC m–2 and allowing to achieve an ionic current rectification ratio of up to 10. This highly versatile technology addresses some of the challenges that contemporary nanopore systems face and offers a platform to improve the performance of existing applications, including nanofluidic osmotic power generation and electroosmotic pumps.

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“…Selectivity of epitaxial layers is typically achieved by adding HCl to the growth chemistry, resulting in etching materials deposited on oxide and nitride surfaces. Since HCl becomes completely ineffective, Cl2 is used as an etching gas for selective epi schemes below 450°C [6,15] and the co-flow approach is replaced by a cyclic deposition/etch approach.…”

Section: Wrap Around S/d Contacts Enabled By Low Temperature Selectiv...mentioning

confidence: 99%

(Invited) Cutting-Edge Epitaxial Processes for Sub 3 Nm Technology Nodes: Application to Nanosheet Stacks and Epitaxial Wrap-Around Contacts

Hikavyy

Porret

Mencarelli³

et al. 2021

ECS Trans.

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This work reports on low temperature epitaxial growth solutions for the processing of advanced CMOS devices beyond the 3 nm technological node. The complex stacking of highly compositionally contrasted strained group IV materials is first demonstrated at 500C. It enables the formation of active nanosheet channels with bottom isolation, necessary for ultimate transistor scaling. Using high order Si and Ge precursors also offers great opportunities for the epitaxy of advanced source/drain materials. It allows achieving hole active concentrations as high as 1.3x10 21 cm -3 in in-situ B-doped Si0.5Ge0.5, providing Ti / SiGe:B contacts with low specific resistivity. Grown at temperatures as low as 400C, the epilayers deposit in a conformal manner, thereby wrapping high aspect ratio 3-dimensional structures and maximizing the contact areas, being an additional option to further decrease device access resistances. As an alternative to B-doping only, we also demonstrate uniformly Ga-doped materials with concentrations ~ 1x10 20 cm -3 . B and Ga are finally combined to co-dope SiGe and further reduce the Ti / p-SiGe contact resistivity.

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Chlorine Etching for In-Situ Low-Temperature Silicon Surface Cleaning for Epitaxy Applications

Cited by 8 publications

References 4 publications

Investigation of Cl₂etch in view of extremely low temperature selective epitaxial processes

Investigation of Cl₂etch in view of extremely low temperature selective epitaxial processes

Highly Rectifying Conical Nanopores in Amorphous SiO₂ Membranes for Nanofluidic Osmotic Power Generation and Electroosmotic Pumps

(Invited) Cutting-Edge Epitaxial Processes for Sub 3 Nm Technology Nodes: Application to Nanosheet Stacks and Epitaxial Wrap-Around Contacts

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Chlorine Etching for In-Situ Low-Temperature Silicon Surface Cleaning for Epitaxy Applications

Cited by 8 publications

References 4 publications

Investigation of Cl2etch in view of extremely low temperature selective epitaxial processes

Investigation of Cl2etch in view of extremely low temperature selective epitaxial processes

Highly Rectifying Conical Nanopores in Amorphous SiO2 Membranes for Nanofluidic Osmotic Power Generation and Electroosmotic Pumps

(Invited) Cutting-Edge Epitaxial Processes for Sub 3 Nm Technology Nodes: Application to Nanosheet Stacks and Epitaxial Wrap-Around Contacts

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Investigation of Cl₂etch in view of extremely low temperature selective epitaxial processes

Investigation of Cl₂etch in view of extremely low temperature selective epitaxial processes

Highly Rectifying Conical Nanopores in Amorphous SiO₂ Membranes for Nanofluidic Osmotic Power Generation and Electroosmotic Pumps