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Device Fabrication |
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The device fabrication facilities at USC's SiC lab are an ideal supplement to the material work of the group. Devices can be fabricated to study device performance - defect correlation which enables us to determine the types of defects that are responsible for poor device performance or failure. Then, further research focuses on the design of material and device structures than can improve device performance both in the short term as well as in the long term. |
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E-Beam System The E-Beam evaporation system is used to deposit metal as well as insulating films for device fabrication purposes. An electron beam strikes source material in a high vacuum, heating it locally in the vicinity of the beam until it begins to evaporate. A sample is held above the heated source and the material deposits uniformly across the surface. |
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RF Magnetron Sputtering Like the E-Beam System, the sputter deposition system is used to deposit metallic and non-metallic films. The difference is that the sputtering system creates an RF plasma of ionized particles that bombard a target. These ions carry with them high kinetic energy and literally knock particles off of the target. These particles then deposit on the sample.
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RIE Reactive Ion Etching creates a plasma similar to the sputter deposition system but for the purpose of etching windows into the surface of a sample. For this purpose, fluorinated gasses such as CF4 and SF6 are used to directionally etch the SiC surface. |
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RTP The Rapid Thermal Processing system is used to heat samples to high temperature and cool them quickly. This is needed to make Ohmic contacts and to activate dopants. The high temperature anneals contacts and activates dopants. However, dopant atoms will diffuse if high temperature is maintained for too long. That is why this process is "Rapid." |
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Mask Aligner The mask aligner is used to pattern photo-resist. Resist is deposited onto a sample aligned with a mask, or template. The mask and sample are then exposed to ultraviolet light which either cures or breaks down the photo-resist, depending on the type. The region that was shadowed by the mask creates a pattern on the sample. The sample may then undergo metal deposition or etching that will only affect unmasked areas. |
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Diffusion Furnace The diffusion furnace is a method of introducing dopant atoms into SiC device structures wherein enough thermal energy is provided for boron or aluminum atoms to simply diffuse into the silicon carbide. Although this technique lacks the resolution of ion implantation methods, it is not destructive to the crystalline lattice.
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Oxidation Furnaces These are thermal oxidation furnaces and they are used to grow insulating silicon dioxide layers on SiC. Wet or dry oxidation is performed by introducing pure oxygen or oxygen and water vapor to a sample while it is at high temperature inside the furnace. At the SiC surface, the oxygen reacts creating Si-O bonds and the carbon in the lattice is removed in the form of CO2. This results in a thin layer of amorphous SiO2 on top of the SiC substrate.
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