Reactive ion beam etching of silicon with a new plasma ion source operated with CF4 : SiO2 over Si selectivity and Si surface modification

Lejeune, C; Grandchamp, J. P.; Gilles, Jean-Paul; Collard, Emmanuel; Scheiblin, P.

doi:10.1051/rphysap:01989002403029500

Cited by 7 publications

(5 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Regarding the evolution of the fluorocarbons, even though from Figures 4 and 7 one can deduce that fluorocarbons are continuously deposited during the process, it appears from Figure 7 a that the coverage of the area etched with F increases with respect to that of the fluoropolymer (CFP) deposited. A further insight into the evolution of the process is provided by the atomic ratio F/C presented in Figure 7 c. According to the classification by Marks, 32 our process can be identified as starting with a low-fluorine polymer and ending as a true RIE process. However, our maskless process ends with an extremely high F/C ratio (about 1.5) 34 , 37 (highly fluorinated polymer) with a low expected geometrical aspect ratio.…”

Section: Discussionmentioning

confidence: 88%

“… Atomic concentration ratios as functions of plasma processing time (a) (SiF + SiF 3 )/(CF + CF 2 ), (b) F/Si, C/Si and F/C, (c) SiF–SiC/S, SiF 3 /Si, and SiO 2 /Si. LFP: low-fluorine polymer growth regime following the definition in ref ( 32 ). See text below.…”

Section: Experimental and Resultsmentioning

confidence: 99%

“…On the other hand, Lejeune showed that for a CF 4 plasma at much lower pressure (10 –4 mbar), the predominant species is CF 3+ . 32 With the only purpose to estimate the physical sputtering rate, we assume that the predominant species in our mixture is CF 3 + and that the physical sputtering is given by this ionic species only. In our case, the ion flux could not be directly measured via a Langmuir probe due to the relatively high pressure.…”

Section: Discussionmentioning

confidence: 99%

“…They estimated a total ion flux at the powered electrode of the order of 8 × 10 15 cm –2 s –1 . On the other hand, Lejeune showed that for a CF 4 plasma at much lower pressure (10 –4 mbar), the predominant species is CF 3+ . With the only purpose to estimate the physical sputtering rate, we assume that the predominant species in our mixture is CF 3 + and that the physical sputtering is given by this ionic species only.…”

Section: Discussionmentioning

confidence: 99%

“…A further insight into the evolution of the process is provided by the atomic ratio F/C presented in Figure 7c. According to the classification by Marks, 32 our process can be identified as starting with a low-fluorine polymer and ending as a true RIE process. However, our maskless process ends with an extremely high F/C ratio (about 1.5) 34,37 (highly fluorinated polymer) with a low expected geometrical aspect ratio.…”

Section: + +mentioning

confidence: 99%

See 4 more Smart Citations

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

et al. 2022

View full text Add to dashboard Cite

The process of deep texturization of the crystalline silicon surface is intimately related to its promising diverse applications, such as bactericidal surfaces for integrated lab-on-chip devices and absorptive optical layers (black silicon—BSi). Surface structuring by a maskless texturization appeals as a cost-effective approach, which is up-scalable for large-area production. In the case of silicon, it occurs by means of reactive plasma processes (RIE—reactive-ion etching) using fluorocarbon CF 4 and H 2 as reaction gases, leading to self-assembled cylindrical and pyramidal nanopillars. The mechanism of silicon erosion has been widely studied and described as it is for the masked RIE process. However, the onset of the erosion and the reaction kinetics leading to defined maskless patterning have not been unraveled to date. In this work, we specifically tackle this issue by analyzing the results of three different RIE recipes, specifically designed for the purpose. The mechanism of surface self-nanopatterning is revealed by deeply investigating the physical chemistry of the etching process at the nanoscale and the evolution of surface morphology. We monitored the progress in surface patterning and the composition of the etching plasma at different times during the RIE process. We confirm that nanopattering issues from a net erosion, as contributed by chemical etching, physical sputtering, and by the synergistic plasma effect. We propose a qualitative model to explain the onset, the evolution, and the stopping of the process. As the RIE process is started, a high density of surface defects is initially created at the free silicon surface by energetic ion sputtering. Contextually, a polymeric overlayer is synthesized on the Si surface, as thick as 5 nm on average, and self-aggregates into nanoclusters. The latter phenomenon can be explained by considering that the initial creation of surface defects increases the activation energy for surface diffusion of deposited CF and CF 2 species and prevents them from aggregating into a continuous Volmer–Weber polymeric film. The clusterization of the polymer provides the self-masking effect since the beginning, which eventually triggers surface patterning. Once started, the maskless texturing proceeds in analogy with the masked case, that is, by combined chemical etching and ion sputtering, and ceases because of the loss of ion energy. In the case of CF 4 /H 2 RIE processes at 10% of H 2 and by supplying 200 W of RF power for 20 min, nanopillars of 200 nm in height and 100 nm in width were formed. We therefore propose that a precise assessment of surface defect formation and density in dependence on the initial RIE process parameters can be the key to open a full control of outcomes of maskless patterning.

show abstract

Section: Discussionmentioning

confidence: 88%

Section: Experimental and Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: + +mentioning

confidence: 99%

See 3 more Smart Citations

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

et al. 2022

View full text Add to dashboard Cite

show abstract

CF incorporated overlayer growth on silicon exposed to a d.c.-excited CF4 plasma

et al. 1990

View full text Add to dashboard Cite

Highly selective SiO2/Si reactive ion beam etching withlow energy fluorocarbon ions

Collard¹,

Lejeune²,

Grandchamp³

et al. 1990

Thin Solid Films

View full text Add to dashboard Cite

Reactive ion beam etching of silicon with a new plasma ion source operated with CF4 : SiO2 over Si selectivity and Si surface modification

Cited by 7 publications

References 21 publications

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

CF incorporated overlayer growth on silicon exposed to a d.c.-excited CF4 plasma

Highly selective SiO2/Si reactive ion beam etching withlow energy fluorocarbon ions

Contact Info

Product

Resources

About

Reactive ion beam etching of silicon with a new plasma ion source operated with CF4 : SiO2 over Si selectivity and Si surface modification

Cited by 7 publications

References 21 publications

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF4/H2 Plasma Reactive-Ion Etching

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF4/H2 Plasma Reactive-Ion Etching

CF incorporated overlayer growth on silicon exposed to a d.c.-excited CF4 plasma

Highly selective SiO2/Si reactive ion beam etching withlow energy fluorocarbon ions

Contact Info

Product

Resources

About

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching