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In the high voltage field, particularly for high-voltage devices above 20,000V, the SiC epitaxial technology still faces several challenges. One of the main difficulties is achieving high uniformity, thickness, and doping concentration in the epitaxial layer. For the fabrication of such high-voltage devices, a 200um thick silicon carbide epitaxial wafer with excellent uniformity and concentration is required.

Gallium oxide (Ga2O3) as an "ultra-wide bandgap semiconductor" material has garnered sustained attention. Ultra-wide bandgap semiconductors fall under the category of "fourth-generation semiconductors," and in comparison to third-generation semiconductors such as silicon carbide (SiC) and gallium nitride (GaN), gallium oxide boasts a bandgap width of 4.9eV, surpassing silicon carbide's 3.2eV and gallium nitride's 3.39eV. A wider bandgap implies that electrons require more energy to transition from the valence band to the conduction band, endowing gallium oxide with characteristics like high voltage resistance, high-temperature tolerance, high power capability, and radiation resistance.

Epitaxial growth refers to the process of growing a crystallographically well-ordered monocrystalline layer on a substrate. Generally speaking, epitaxial growth involves the cultivation of a crystal layer on a single-crystal substrate, with the grown layer sharing the same crystallographic orientation as the original substrate. Epitaxy is extensively utilized in semiconductor manufacturing, such as the production of epitaxial silicon wafers in the integrated circuit industry.

The history of silicon carbide (SiC) dates back to 1891, when Edward Goodrich Acheson accidentally discovered it while attempting to synthesize artificial diamonds. Acheson heated a mixture of clay (aluminosilicate) and powdered coke (carbon) in an electric furnace. Instead of the expected diamonds, he obtained a bright green crystal adhering to the carbon. This crystal had a hardness second only to diamond, and was thus named carborundum. In 1904, French-Jewish chemist Henri Moissan discovered rare natural silicon carbide minerals while studying meteorite samples from the Diablo Canyon in Arizona, USA. He named these minerals moissanite, and his discovery earned him the 1906 Nobel Prize in Chemistry.

Oxidation processes play a critical role in preventing such problems by creating a protective layer on the wafer, known as the oxide layer, which acts as a barrier between different chemicals.