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| substrate:start [2016/01/12 08:55] – james | substrate:start [2020/07/03 11:31] (current) – [Cleaving Substrates] janet |
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| * [[http://www.mtixtl.com/ysz.aspx|YSZ]] (100), (111), (110) | * [[http://www.mtixtl.com/ysz.aspx|YSZ]] (100), (111), (110) |
| * [[http://www.mtixtl.com/srtio3.aspx|SrTiO3]] (100), (110) | * [[http://www.mtixtl.com/srtio3.aspx|SrTiO3]] (100), (110) |
| * ITO-coated glass (ITO = indium tin oxide or In2O3:Sn) | * [[http://delta-technologies.com/default.asp|ITO-coated glass]] (ITO = indium tin oxide or In2O3:Sn)(Delta Tech. X189: CG-61IN, Polished Float Glass, SiO2 passivated/ITO coated on polished surface, Rs = 15 - 25 ohms, 25 x 25 x 0.7 mm, ITO coatings on these slides are 600 to 1000 Angstroms) |
| * Glasses ([[http://www.sgpinc.com/materials.htm|Physical Properties]] and terminology) | * Glasses ([[http://www.sgpinc.com/materials.htm|Physical Properties]] and terminology) |
| * Fused silica (SiO2) | * [[http://www.gmassoc.com/index.html|Fused silica (a:SiO2), and Crystalline Quartz]] |
| * Borosilicate glass (BK7) | * [[http://www.tedpella.com/histo_html/slides-large.htm|Borosilicate Crown glass (BK7)]] |
| * Soda Lime Glass | * [[http://www.tedpella.com/technote_html/0215%20corning%20glass.pdf|Soda Lime Glass]] |
| * Corning 1737 | * [[http://www.vinkarola.com/pdf/Corning%20Glass%201737%20Properties.pdf|Corning 1737]] |
| | * [[https://www.corning.com/media/worldwide/cdt/documents/EAGLE%20XG%20%C2%AE%20Slim%20Glass.pdf|Corning Eagle XG]] |
| * [[http://www.mtixtl.com/caf2.aspx|CaF2]] | * [[http://www.mtixtl.com/caf2.aspx|CaF2]] |
| * FTO (SnO2:F) | * FTO (SnO2:F) |
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| | If you find a substrate and you do not know what it is made of, one way to quickly identify the material is by exposure to UV light. The image below is an example of two different substrates side-by-side during deposition with a UV laser. The aspect to look at here is the outline of the substrate. The one that appears to have a purple outline is a-SiO2, while the substrate with a yellowish outline is SLS glass. Eagle XG glass looks similar to SLS. {{:substrate:glass_luminescence.jpeg? 400|}} |
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| ===== Suppliers ===== | ===== Suppliers ===== |
| ====== Cleaning Procedures ====== | ====== Cleaning Procedures ====== |
| {{:substrate:piranha.pdf|Acidic Piranha Procedure}} - A very aggressive cleaning procedure for removing organics from substrates. Note: this is an exception to the "Add Acid" rule. The reaction is highly exothermic and can boil and potentially explode if the peroxide concentration is too high. Substrates should be reasonably clean (i.e. not covered in fingerprints) before going into the solution - large quantities of organic materials will result in violent reactions. | {{:substrate:piranha.pdf|Acidic Piranha Procedure}} - A very aggressive cleaning procedure for removing organics from substrates. Note: this is an exception to the "Add Acid" rule. The reaction is highly exothermic and can boil and potentially explode if the peroxide concentration is too high. Substrates should be reasonably clean (i.e. not covered in fingerprints) before going into the solution - large quantities of organic materials will result in violent reactions. |
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| | {{:substrate:sop-wet-cleaning-pro-for-glass-substrates.pdf|UC Irvine glass substrate cleaning procedures}} gives a few different options as far as cleaning glass substrates. These procedures include the RCA clean procedure described below followed by different acid treatments to remove any final organic compounds on the surfaces of the substrates. |
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| ===Chris' Notes on Cleaning=== | ===Chris' Notes on Cleaning=== |
| To clean substrate materials like fused silica or Si wafers, it is important to begin with a series of solvent baths. Typically, trichloroethylene (colloquially called trico), acetone, and methanol are used sequentially for 5 minutes each as a sonication bath for one's substrates. This procedure is recommended by Werner Kern, creator of the RCA clean. One may wish to follow these solvent baths with isopropanol; this cleaning method is then called the TAMI clean. It is important to note that for the highest quality surfaces, normal ACS grade solvents are inadequate. HLPC grade or better solvents should be used; these come in a glass bottle typically, and should not be stored in plastic squeeze bottles. | To clean substrate materials like fused silica or Si wafers, it is important to begin with a series of solvent baths. Typically, trichloroethylene (colloquially called trico), acetone, and methanol are used sequentially for 5 minutes each as a sonication bath for one's substrates. This procedure is recommended by Werner Kern, creator of the RCA clean. One may wish to follow these solvent baths with isopropanol; this cleaning method is then called the TAMI clean. It is important to note that for the highest quality surfaces, normal ACS grade solvents are inadequate. HLPC grade or better solvents should be used; these come in a glass bottle typically, and should not be stored in plastic squeeze bottles. |
| FIXME more ... | FIXME more ... |
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| ====== Si: Cleaning Procedures that remove the native oxide ====== | ===== Si: Cleaning Procedures that remove the native oxide ===== |
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| This section details some wisdom about cleaning of Si surfaces for the purpose of remove oxides to study reconstructed surfaces or to passivate them. | This section details some wisdom about cleaning of Si surfaces for the purpose of remove oxides to study reconstructed surfaces or to passivate them. |
| Today we have had increased success finding LEED patterns by removing a purposefully grown "volatile oxide" layer from the silicon wafer by similarly flashing the wafer to high temperature in vacuum..even seeing some secondary diffraction spots! Our research will probably continue in this direction. i.e. - thermally blasting the si substrates as a final cleaning step. | Today we have had increased success finding LEED patterns by removing a purposefully grown "volatile oxide" layer from the silicon wafer by similarly flashing the wafer to high temperature in vacuum..even seeing some secondary diffraction spots! Our research will probably continue in this direction. i.e. - thermally blasting the si substrates as a final cleaning step. |
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| | ====== Cleaving Substrates ====== |
| | It is often necessary to cut a substrate or substrate + film into smaller pieces, a process called cleaving. It is easiest to cleave single-crystal substrates along directions that coincide with the major lattice planes, e.g. [100] silicon. Such breaks are typically very clean. Cleaving along random directions is harder. Amorphous substrates like glass can also be cleaved, and the edge tends to be less straight, but you get better with practice. It all depends on the pressure of that single scribe. |
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| | Always scribe on the NON-film side of the substrate. Put the film side on a clean, soft, preferably lint-free cloth. |
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| | This video from Okan Agirseven describes cleaving an amorphous SiO2 substrate in the Tate lab: |
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| | {{ :substrate:okan_agirseven-glass_sample_cleaving_tutorial-2020-06-30.mp4 |Okan describes cleaving}} |
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| | The basic implements are |
| | * A steel straight-edge ruler |
| | * A diamond scribe pen |
| | * Cleaving pliers (which supply a bevel at the scribe position and apply pressure on both sides to break) |
| | A cleaving kit can be purchased from Electron Microscopy Sciences [[https://www.emsdiasum.com/microscopy/products/cleaving/accessories.aspx]] |
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| | This description of the {{ :substrate:cleaving_substrates_for_photonics_com.pdf |cleaving process for single-crystal and amorphous substrates}} comes from Lattice Gear, which also sells cleaving kits. |
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| | University Wafer has a [[https://www.universitywafer.com/cleaving-silicon-wafers.html|website that describes cleaving silicon wafers]] (much easier than amorphous substrates). It has some good images and a fun-to-watch video. |
