Carfagno, HenryMcCabe, LaurenZide, JoshuaDoty, Matthew F.2022-10-112022-10-112022-09-21Carfagno, Henry, Lauren McCabe, Joshua Zide, and Matthew F Doty. “A Sleeve and Bulk Method for Fabrication of Photonic Structures with Features on Multiple Length Scales.” Nanotechnology, September 21, 2022. https://doi.org/10.1088/1361-6528/ac9391.1361-6528https://udspace.udel.edu/handle/19716/31467This is the Accepted Manuscript version of an article accepted for publication in Nanotechnology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-6528/ac9391. This article will be embargoed until 09/21/2023.Traditional photonic structures such as photonic crystals utilize a) large arrays of small features with the same size and pitch and b) a small number of larger features such as diffraction outcouplers. In conventional nanofabrication, separate lithography and etch steps are used for small and large features in order to employ process parameters that lead to optimal pattern transfer and side-wall profiles for each feature-size category, thereby overcoming challenges associated with RIE lag. This approach cannot be scaled to more complex photonic structures such as those emerging from inverse design protocols. Those structures include features with a large range of sizes such that no distinction between small and large can be made. We develop a sleeve and bulk etch protocol that can be employed to simultaneously pattern features over a wide range of sizes while preserving the desired pattern transfer fidelity and sidewall profiles. This approach reduces the time required to develop a robust process flow, simplifies the fabrication of devices with wider ranges of feature sizes, and enables the fabrication of devices with increasingly complex structure.en-USArticle