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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).

In semiconductor fabrication, etching is one of the major steps, along with photolithography and thin-film deposition. It involves removing unwanted materials from the surface of a wafer using chemical or physical methods. This step is carried out after coating, photolithography, and developing. It is used to remove the exposed thin film material, leaving only the desired portion of the wafer, and then removing the excess photoresist. These steps are repeated numerous times to create complex integrated circuits.

In semiconductor manufacturing, atomic-level flatness is usually used to describe the global flatness of the wafer, with the unit of nanometers (nm).

Within the silicon carbide (SiC) industry chain, substrate suppliers hold significant leverage, primarily due to value distribution. SiC substrates account for 47% of the total value, followed by epitaxial layers at 23%, while device design and manufacturing constitute the remaining 30%. This inverted value chain stems from the high technological barriers inherent to substrate and epitaxial layer production. Three major challenges plague SiC substrate growth: stringent growth conditions, slow growth rates, and demanding crystallographic requirements. These complexities contribute to increased processing difficulty, ultimately resulting in low product yields and high costs. Furthermore, the epitaxial layer’s thickness and doping concentration are critical parameters directly impacting the final device performance.

4H-SiC, as a third-generation semiconductor material, is renowned for its wide bandgap, high thermal conductivity, and excellent chemical and thermal stability, making it highly valuable in high-power and high-frequency applications.

Semiconductors are materials whose electrical conductivity at room temperature lies between that of insulators and conductors. By introducing impurities, a process known as doping, these materials can become conductors.