Porous Tantalum carbide TaC

Semixlab has introduced a porous graphite material coated with tantalum carbide (TaC). It utilizes a porous graphite skeleton with controllable porosity (50%–75%) to leverage its large specific surface area for gas-phase flow guidance and filtration. Through CVD technology, a dense TaC coating (melting point: 3880 °C) is deposited on both internal and external surfaces, endowing the material with exceptional high-temperature resistance and H₂ corrosion resistance (more than 10 times higher than conventional SiC coatings). A unique gradient transition layer design ensures a smooth transition of the thermal expansion coefficient, preventing the coating from cracking or peeling under repeated thermal shocks. This structure enables four core functions in SiC crystal growth: acting as a high-precision filter to block particulate impurities, precisely regulating the temperature field via TaC's high thermal conductivity to control growth rate, guiding directional gas-phase flow through the pore structure to promote uniform crystal growth, and maintaining a stable atmosphere through the synergy of the dense surface and porous interior, thereby significantly improving crystal yield and process reproducibility.

Typical scheme of the TaC deposition unit: (a) in situ chlorination device; (b) CVD reactor.

Application Scenarios

1. Core Application: PVT SiC Single Crystal Growth

In the process of SiC single crystal growth by PVT (Physical Vapor Transport) method, our products are mainly used as thermal field components such as porous crucibles, crucible lids, flow guide tubes, and trays. Compared with traditional graphite materials, they can eliminate carbon inclusions by blocking carbon particles from entering the crystal to significantly reduce micropipe defects, prevent etch pit formation by maintaining structural integrity during long-cycle growth to avoid polycrystallization, and improve yield by providing a purer growth environment to enhance crystal quality and production efficiency.

2. Expanded Application

①Semiconductor Epitaxy Equipment

In the SiC epitaxy process (LPE, MOCVD equipment), our materials can be used as heaters, graphite trays, and reaction chamber liners. The NH₃ corrosion resistance of the TaC coating effectively protects graphite components, prevents impurity contamination, and extends component service life, ensuring stable operation of epitaxy equipment.

②PV Coating Equipment

In the PECVD process of photovoltaic cell manufacturing, our products can be used as coating materials for graphite boats and carrier plates. They resist etching by fluorine-containing/chlorine-containing plasmas, avoid graphite powder falling to contaminate silicon wafers, and are suitable for high-efficiency cell processes such as PERC and HJT, contributing to the improvement of photovoltaic cell quality.