Scalable Fabrication of Nanogratings on GaP for Efficient Diffraction of Near-Infrared Pulses and Enhanced Terahertz Generation by Optical Rectification
We present a process flow for wafer-scale fabrication of a surface phase grating with sub-micron feature sizes from a single semiconductor material. We demonstrate this technique using a 110-oriented GaP semiconductor wafer with second-order nonlinearity to obtain a nanostructured device (800 nm lat...
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MDPI AG
2022-05-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/12/5/684 |
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| author | Mohammad Bashirpour Wei Cui Angela Gamouras Jean-Michel Ménard |
| author_facet | Mohammad Bashirpour Wei Cui Angela Gamouras Jean-Michel Ménard |
| author_sort | Mohammad Bashirpour |
| collection | DOAJ |
| description | We present a process flow for wafer-scale fabrication of a surface phase grating with sub-micron feature sizes from a single semiconductor material. We demonstrate this technique using a 110-oriented GaP semiconductor wafer with second-order nonlinearity to obtain a nanostructured device (800 nm lateral feature size and a 245 nm height modulation) with applications relevant to near-infrared optical diffraction and time-resolved terahertz (THz) technologies. The fabrication process involves a plasma-enhanced chemical deposition of a SiO<sub>2</sub> layer on the wafer followed by contact photolithography and inductively coupled plasma reactive ion etching (ICP-RIE). We discuss the required radiation dosage, exposure times, temperatures and other key parameters to achieve high-quality nanogratings in terms of filling ratio, edge profile, and overall shape. The phase-grating properties, such as the pitch, spatial homogeneity, and phase retardation, are characterized with an atomic force microscope, scanning electron microscope and a non-invasive optical evaluation of the optical diffraction efficiency into different orders. We demonstrate an application of this device in a time-domain THz spectroscopy scheme, where an enhanced THz spectral bandwidth is achieved by optical rectification of near-infrared laser pulses incident on the grating and efficiently diffracted into the first orders. Finally, the reported process flow has the potential to be applied to various materials by considering only slight adjustments to the ICP-RIE etching steps, paving the way to scalable fabrication of sub-micron patterns on a large range of substrates. |
| first_indexed | 2024-03-10T03:05:23Z |
| format | Article |
| id | doaj.art-fcef3329902c488b82fb6b2d10061f5a |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T03:05:23Z |
| publishDate | 2022-05-01 |
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| series | Crystals |
| spelling | doaj.art-fcef3329902c488b82fb6b2d10061f5a2023-11-23T10:35:26ZengMDPI AGCrystals2073-43522022-05-0112568410.3390/cryst12050684Scalable Fabrication of Nanogratings on GaP for Efficient Diffraction of Near-Infrared Pulses and Enhanced Terahertz Generation by Optical RectificationMohammad Bashirpour0Wei Cui1Angela Gamouras2Jean-Michel Ménard3Department of Physics, University of Ottawa, Ottawa, ON K1N 7N9, CanadaDepartment of Physics, University of Ottawa, Ottawa, ON K1N 7N9, CanadaDepartment of Physics, University of Ottawa, Ottawa, ON K1N 7N9, CanadaDepartment of Physics, University of Ottawa, Ottawa, ON K1N 7N9, CanadaWe present a process flow for wafer-scale fabrication of a surface phase grating with sub-micron feature sizes from a single semiconductor material. We demonstrate this technique using a 110-oriented GaP semiconductor wafer with second-order nonlinearity to obtain a nanostructured device (800 nm lateral feature size and a 245 nm height modulation) with applications relevant to near-infrared optical diffraction and time-resolved terahertz (THz) technologies. The fabrication process involves a plasma-enhanced chemical deposition of a SiO<sub>2</sub> layer on the wafer followed by contact photolithography and inductively coupled plasma reactive ion etching (ICP-RIE). We discuss the required radiation dosage, exposure times, temperatures and other key parameters to achieve high-quality nanogratings in terms of filling ratio, edge profile, and overall shape. The phase-grating properties, such as the pitch, spatial homogeneity, and phase retardation, are characterized with an atomic force microscope, scanning electron microscope and a non-invasive optical evaluation of the optical diffraction efficiency into different orders. We demonstrate an application of this device in a time-domain THz spectroscopy scheme, where an enhanced THz spectral bandwidth is achieved by optical rectification of near-infrared laser pulses incident on the grating and efficiently diffracted into the first orders. Finally, the reported process flow has the potential to be applied to various materials by considering only slight adjustments to the ICP-RIE etching steps, paving the way to scalable fabrication of sub-micron patterns on a large range of substrates.https://www.mdpi.com/2073-4352/12/5/684photolithographynanogratinggallium phosphide waferdiffraction efficiencytime-resolved terahertz |
| spellingShingle | Mohammad Bashirpour Wei Cui Angela Gamouras Jean-Michel Ménard Scalable Fabrication of Nanogratings on GaP for Efficient Diffraction of Near-Infrared Pulses and Enhanced Terahertz Generation by Optical Rectification Crystals photolithography nanograting gallium phosphide wafer diffraction efficiency time-resolved terahertz |
| title | Scalable Fabrication of Nanogratings on GaP for Efficient Diffraction of Near-Infrared Pulses and Enhanced Terahertz Generation by Optical Rectification |
| title_full | Scalable Fabrication of Nanogratings on GaP for Efficient Diffraction of Near-Infrared Pulses and Enhanced Terahertz Generation by Optical Rectification |
| title_fullStr | Scalable Fabrication of Nanogratings on GaP for Efficient Diffraction of Near-Infrared Pulses and Enhanced Terahertz Generation by Optical Rectification |
| title_full_unstemmed | Scalable Fabrication of Nanogratings on GaP for Efficient Diffraction of Near-Infrared Pulses and Enhanced Terahertz Generation by Optical Rectification |
| title_short | Scalable Fabrication of Nanogratings on GaP for Efficient Diffraction of Near-Infrared Pulses and Enhanced Terahertz Generation by Optical Rectification |
| title_sort | scalable fabrication of nanogratings on gap for efficient diffraction of near infrared pulses and enhanced terahertz generation by optical rectification |
| topic | photolithography nanograting gallium phosphide wafer diffraction efficiency time-resolved terahertz |
| url | https://www.mdpi.com/2073-4352/12/5/684 |
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