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We know that further epitaxial layers need to be built on top of some wafer substrates for device fabrication, typically LED light-emitting devices, which require GaAs epitaxial layers on top of silicon substrates; SiC epitaxial layers are grown on top of conductive SiC substrates for building devices such as SBDs, MOSFETs, etc. for high voltage, high current and other power applications; GaN epitaxial layers are built on top of semi-insulating SiC substrates for building HEMTs and other RF applications.

At first glance, quartz (SiO2) material looks very similar to glass, but what is special is that ordinary glass is composed of many components (such as quartz sand, borax, boric acid, barite, barium carbonate, limestone, feldspar, soda ash, etc.), while quartz only contains SiO2, and its microstructure is a simple network composed of silicon dioxide tetrahedral structural units.

In the semiconductor industry, epitaxial layers play a crucial role by forming specific single-crystal thin films atop a wafer substrate, collectively known as epitaxial wafers. Particularly, silicon carbide (SiC) epitaxial layers grown on conductive SiC substrates produce homogenous SiC epitaxial wafers, which are instrumental in the fabrication of power devices such as Schottky diodes, MOSFETs, and IGBTs, with 4H-SiC substrates being the most widely utilized.

The CVD process for SiC wafer epitaxy involves the deposition of SiC films onto a SiC substrate using a gas-phase reaction. The SiC precursor gases, typically methyltrichlorosilane (MTS) and ethylene (C2H4), are introduced into a reaction chamber where the SiC substrate is heated to a high temperature (usually between 1400 and 1600 degrees Celsius) under a controlled atmosphere of hydrogen (H2).

The third-generation wide bandgap semiconductor materials, such as Gallium Nitride (GaN) and Silicon Carbide (SiC), are renowned for their exceptional optoelectronic conversion and microwave signal transmission capabilities. These materials meet the demanding requirements of high-frequency, high-temperature, high-power, and radiation-resistant electronic devices. Therefore, they have vast application prospects in new-generation mobile communications, new energy vehicles, smart grids, and LED technologies. The comprehensive development of the third-generation semiconductor industry urgently requires breakthroughs in key core technologies, continual advancement in device design and innovation, and a resolution to import dependencies.