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Epitaxial wafer process is a critical technique used in semiconductor manufacturing. It involves the growth of a thin layer of crystal material on top of a substrate, which has the same crystal structure and orientation as the substrate. This process creates a high-quality interface between the two materials, allowing for the development of advanced electronic devices.

The development of high-powered blue and UV LEDs has enabled the creation of full-color LED TV displays, as well as white LED automotive and domestic lighting. These LEDs are based on Gallium Nitride, which is deposited on substrate wafers supported by CVD SiC-coated graphite susceptor using the MOCVD process.

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 Silicon Carbide (SiC) production process encompasses the preparation of substrate and epitaxy from the materials side, followed by chip design and manufacturing, device packaging, and finally, distribution to downstream application markets. Among these stages, substrate material processing is the most challenging aspect of the SiC industry. SiC substrates are both hard and brittle, making cutting, grinding, and polishing extremely difficult. This increases the likelihood of defects during processing and reduces the yield rate. Currently, major international SiC manufacturers are planning to transition from 6-inch to 8-inch SiC wafers. Overcoming the challenges associated with 8-inch substrates has become a critical benchmark for the SiC industry. This article will introduce the key parameters of SiC substrates.

Currently, many semiconductor devices employ mesa device structures, which are predominantly created through two types of etching: wet etching and dry etching. While the simple and rapid wet etching plays a significant role in semiconductor device fabrication, it has inherent drawbacks such as isotropic etching and poor uniformity, which result in limited control when transferring small-sized patterns. Dry etching, however, with its high anisotropy, good uniformity, and repeatability, has become prominent in semiconductor device fabrication processes. The term “dry etching” broadly refers to any non-wet etching technology used for removing surface materials and transferring micro and nano patterns, including laser etching, plasma etching, and chemical vapor etching. The dry etching discussed in this text specifically pertains to the narrow application of processes using plasma discharge—either physical or chemical—to modify material surfaces.

Wide bandgap (WBG) semiconductors such as Silicon Carbide (SiC) and Gallium Nitride (GaN) are expected to play an increasingly important role in power electronic devices. They offer several advantages over traditional Silicon (Si) devices, including higher efficiency, power density, and switching frequency. Ion implantation is the primary method for achieving selective doping in Si devices. However, there are some challenges when applying it to wide bandgap devices. In this article, we will focus on some of these challenges and summarize their potential applications in GaN power devices.