China Epitaxial Sheet Manufacturers, Suppliers, Factory

Thick, high-purity silicon carbide (SiC) layers, typically exceeding 1mm, are critical components in various high-value applications, including semiconductor fabrication and aerospace technologies. This article delves into the Chemical Vapor Deposition (CVD) process for producing such layers, highlighting key process parameters, material characteristics, and emerging applications.

The application areas of SiC-based and Si-based GaN are not strictly separated. In GaN-On-SiC devices, the cost of SiC substrate is relatively high, and with the growing maturity of SiC long crystal technology, the cost of the device is expected to fall further, and it is used in power devices in the field of power electronics.

In the process of growing SiC and AlN single crystals by the physical vapor transport method (PVT), components such as the crucible, seed crystal holder and guide ring play a vital role. During the preparation process of SiC, the seed crystal is located in a relatively low temperature region, while the raw material is in a high temperature region exceeding 2400°C. The raw materials decompose at high temperatures to form SiXCy (including Si, SiC₂, Si₂C and other components).

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.

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.

At present, the most important direction trend of substrate development is to expand the diameter. The 6-inch mass production line in the global SiC market is maturing, and leading companies have entered the 8-inch market.