Fabrication of cone-shaped subwavelength structures by utilizing a confined convective self-assembly technique and inductively coupled-plasma reactive-ion etching

ABSTRACT Cone-shaped subwavelength structures (SWSs) were fabricated on a GaAs substrate by utilizing a confined convective self-assembly process followed by inductively coupled-plasma reactive-ion etching. A self-assembled polystyrene monolayer was used as an etch mask for pattern transfer onto the GaAs substrate. The fabricated SWS, having a cone profile with an aspect ratio of 1.5 and a 300 nm pitch, exhibited very low reflectance throughout the solar spectrum range and exhibited wide tolerance to different optical incidence angles. Reflectance of the cone-shaped SWS on the GaAs surface was less than 4% in a spectral range of 300–1000 nm under a normal incidence condition.

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    ABSTRACT: In this article we report on the fabrication of subwavelength antireflection structures on silicon substrates using a trilayer resist nanoimprint lithography and liftoff process. We have fabricated cone-shaped nanoscale silicon pillars with a continuous effective index gradient, which greatly enhances its antireflective performances. Our measurements show that the two-dimensional subwavelength structure effectively suppresses surface reflection over a wide spectral bandwidth and a large field of view. A reflectivity of 0.3% was measured at 632.8 nm wavelength, which is less than 1% of the flat silicon surface reflectivity. © 2003 American Vacuum Society.
    Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society 01/2003; 21(6). · 1.27 Impact Factor


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