Browsing by Subject "Laser lithography"

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    Investigating the potential of laser-written one-dimensional photonic crystals inside silicon
    (TUBITAK, 2022-08-31) Tokel, Onur
    The field of silicon photonics is based on introducing and exploiting advanced optical functionality. Current efforts in the field are based on conventional micro/nanofabrication methods, leading to optical functionality over wafer surfaces. A complementary and emerging field is introducing analogous optics directly within the wafer using lasers. Here we investigate the theoretical feasibility of a subclass of such optics, photonic crystals. Our efforts will guide future experimental efforts towards in-chip spectral control.
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    Laser lithography of monolithically-integrated multi-level microchannels in silicon
    (Wiley-VCH Verlag GmbH & Co. KGaA, 2024-05-06) Tauseef, Muhammad Ahsan; Asgari Sabet, Rana; Tokel, Onur
    The trend toward ever-increased speeds for microelectronics is challenged by the emergence of heat-wall, leading to the faltering of Moore's Law. A potential solution may be integrating microfluidic channels into silicon (Si), to deliver controlled amounts of cooling fluid and regulate hot spots. Such meandering microfluidic channels within other transparent materials already played significant roles, including in biomedical and sensor applications; however, analogous channel architectures do not exist in Si. Here, a novel method is proposed to fabricate buried microchannel arrays monolithically integrated into Si, without altering the wafer surface. A two-step, laser-assisted subtractive removal method is exploited, enabling fully-buried multi-level architectures, with control on the channel port geometry, depth, curvature, and aspect ratio. The selective removal rate is 750 µm per h per channel, and the channel inner-wall roughness is 230 nm. The method preserves top wafer surface roughness of 2 nm, with significant potential for 3D integrated systems.