China radial shaft seal ring Manufacturers, Suppliers, Factory

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.

The single crystal growth furnace is composed of six key systems that work in harmony to ensure efficient and high-quality crystal growth.

The three primary methods used in monocrystalline silicon manufacturing are the Czochralski (CZ) method, the Kyropoulos method, and the Float Zone (FZ) method.

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.

Specialty graphite is graphite with carbon mass fraction greater than 99.99%, also known as "three high graphite" (high strength, high density, high purity). It is characterized by high strength, high density, high purity, high chemical stability, high thermal and electrical conductivity, high temperature resistance, radiation resistance, strong lubrication and easy processing. Isostatic graphite belongs to specialty graphite.

SiC's own characteristics determine its single crystal growth is more difficult. Due to the absence of Si:C=1:1 liquid phase at atmospheric pressure, the more mature growth process adopted by the mainstream of the semiconductor industry can not be used to grow the more mature growth method-straight pulling method, the descending crucible method and other methods for growth. After theoretical calculations, only when the pressure is greater than 105 atm and the temperature is higher than 3200 ℃, can we get the stoichiometric ratio of Si:C = 1:1 solution. pvt method is currently one of the more mainstream methods.