Silicon nanostructures with very large negatively tapered profile by inductively coupled plasma-RIE

Ayari-Kanoun, Asma; Aydinoglu, Ferhat; Cui, Bo; Saffih, Faycal

doi:10.1116/1.4964402

Cited by 20 publications

(8 citation statements)

References 21 publications

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“…Compared to conventional Si RIE using CF 4 /O 2 gas, the nonswitching pseudo-Bosch ICP-RIE offers about 3× higher selectivity between Si and Al. Moreover, by adjusting the etching parameters notably the SF 6 /C 4 F 8 ratio, it can give a smooth and vertical sidewall profile, a broadly tunable tapered profile, or even a negatively tapered profile (inverse cone shape). , …”

Section: Resultsmentioning

confidence: 99%

Single Layer Surface-Grafted PMMA as a Negative-Tone e-Beam Resist

et al. 2017

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One of the important challenges in electron beam lithography is nanofabrication on nonflat or irregular surfaces. Although spin coating is the most popular technique for resist coating, it is not suitable for nonflat, irregular substrates because a uniform film cannot be achieved on those surfaces. Here, it is demonstrated that single layer surface-grafted PMMA can be used as a negative-tone e-beam resist, and it can be applied to nonflat, irregular surfaces as well as flat, conventional surfaces. Although it is well known that heavily exposed PMMA undergoes cross-linking and works as a negative-tone e-beam resist when developed by solvent, solvent does not work as a developer for negative-tone single-layer surface-grafted PMMA. Instead, thermal treatment at 360 °C for 1 min is used to develop PMMA.

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Section: Resultsmentioning

confidence: 99%

Single Layer Surface-Grafted PMMA as a Negative-Tone e-Beam Resist

et al. 2017

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“…Hence, we modified the etching process to fabricate such cone-shaped pillars. Previously, we have reported inductively coupled plasma reactive ion etching (ICP-RIE) of silicon to give a broadly tunable tapered profile or even a negatively tapered profile (inverse cone shape) [ 28 , 29 ]. Using the reported etching recipe, resulted structures are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Surface Nanostructures Formed by Phase Separation of Metal Salt–Polymer Nanocomposite Film for Anti-reflection and Super-hydrophobic Applications

Con

Cui

2017

Nanoscale Res Lett

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This paper describes a simple and low-cost fabrication method for multi-functional nanostructures with outstanding anti-reflective and super-hydrophobic properties. Our method employed phase separation of a metal salt–polymer nanocomposite film that leads to nanoisland formation after etching away the polymer matrix, and the metal salt island can then be utilized as a hard mask for dry etching the substrate or sublayer. Compared to many other methods for patterning metallic hard mask structures, such as the popular lift-off method, our approach involves only spin coating and thermal annealing, thus is more cost-efficient. Metal salts including aluminum nitrate nonahydrate (ANN) and chromium nitrate nonahydrate (CNN) can both be used, and high aspect ratio (1:30) and high-resolution (sub-50 nm) pillars etched into silicon can be achieved readily. With further control of the etching profile by adjusting the dry etching parameters, cone-like silicon structure with reflectivity in the visible region down to a remarkably low value of 2% was achieved. Lastly, by coating a hydrophobic surfactant layer, the pillar array demonstrated a super-hydrophobic property with an exceptionally high water contact angle of up to 165.7°.

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“…This nonswitching ICP-RIE process using SF 6 and C 4 F 8 gas is very versatile, offering a broadly tunable sidewall taper angles from large positive (cone structure) to large negative (inverse cone structure). 2,20,21…”

Section: Methodsmentioning

confidence: 99%

Chromium oxide as a hard mask material better than metallic chromium

Aydinoglu

Saffih

Dey

et al. 2017

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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In nanofabrication, use of thin resist is required to achieve very high resolution features. But thin resist makes pattern transferring by dry etching difficult because typical resist has poor resistance to plasma etching. One widely employed strategy is to use an intermediate hard mask layer, with the pattern first transferred into this layer, then into the substrate or sublayer. Cr is one of the most popular hard etching mask materials because of its high resistance to plasma etching. Cr etching is carried out in O 2 and Cl 2 or CCl 4 environment to form the volatile etching product CrO 2 Cl 2 , but addition of O 2 gas leads to fast resist etching. In this work, the authors show that Cr 2 O 3 can be etched readily in a Cl 2 /O 2 gas mixture with less oxygen than needed for Cr etching, because Cr 2 O 3 contains oxygen by itself. Thus it is easier to transfer the resist pattern into Cr 2 O 3 than into Cr. For the subsequent pattern transferring into the substrate here silicon using nonswitching pseudo-Bosch inductively coupled plasma-reactive ion etching with SF 6 /C 4 F 8 gas and Cr or Cr 2 O 3 as mask, it was found that the two materials have the same etching resistance and selectivity of 100:1 over silicon. Therefore, Cr 2 O 3 is a more suitable hard mask material than Cr for pattern transferring using dry plasma etching.

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Silicon nanostructures with very large negatively tapered profile by inductively coupled plasma-RIE

Cited by 20 publications

References 21 publications

Single Layer Surface-Grafted PMMA as a Negative-Tone e-Beam Resist

Single Layer Surface-Grafted PMMA as a Negative-Tone e-Beam Resist

Surface Nanostructures Formed by Phase Separation of Metal Salt–Polymer Nanocomposite Film for Anti-reflection and Super-hydrophobic Applications

Chromium oxide as a hard mask material better than metallic chromium

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