China thermal stability 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 most basic stage of all processes is the oxidation process. The oxidation process is to place the silicon wafer in an atmosphere of oxidants such as oxygen or water vapor for high-temperature heat treatment (800~1200℃), and a chemical reaction occurs on the surface of the silicon wafer to form an oxide film (SiO2 film).

When cleaning wafers, ultrasonic cleaning and megasonic cleaning are commonly used to remove particles from the wafer surface.

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.

When producing large-sized GaN single crystal substrates, HVPE is currently the best choice for commercialization. However, the back carrier concentration of the grown GaN cannot be precisely controlled.