4 results about "Carbon contamination" patented technology

The application belongs to the technical field of rare earth metallurgy, and discloses a method for preparing rare earth metal by electrolyzing molten salt. The method comprises the following steps: taking rare earth oxide as electrolytic raw material, and performing electrolysis in molten salt electrolyte under a protective atmosphere; and collecting the deposit after electrolysis, so that the rare earth metal is obtained. Through the synergistic effect of multi-dimensional process, the application successfully constructs an efficient, green and stable rare earth metal electrolysis preparation system. The system completely eliminates carbon pollution, significantly improves the stability of the electrolysis process and the quality of the product, realizes efficient and stable preparation of high-purity rare earth metal, and can meet the stringent requirements of high-end electronics, aerospace, high-performance permanent magnet materials and other fields for ultra-high-purity rare earth products.

A method for removing carbon contamination from a silicon carbide chip includes: providing a substrate having opposing first and second surfaces; forming a device layer on the first surface of the substrate, the device layer having a source doped region; forming an interlayer dielectric layer on the source doped region; etching the interlayer dielectric layer to expose the surface of the source doped region, forming a contact hole; forming a first metal layer at the bottom of the contact hole; heat-treating the first metal layer and the source doped region to form a first ohmic contact layer and a first carbon contamination layer on the surface of the first ohmic contact layer; and performing a plasma gas cleaning operation to remove the first carbon contamination layer. Since the plasma gas cleaning operation is a dry removal method, specifically involving low-energy ion bombardment to remove the first carbon contamination layer, it can remove the first carbon contamination layer while avoiding damage to the first ohmic contact layer at the bottom of the first carbon contamination layer and the surface of the source doped region, thereby improving the electrical performance and reliability of the silicon carbide chip.

This invention discloses a SiC substrate MOCVD gallium oxide epitaxial wafer, belonging to the field of wide-bandgap semiconductor epitaxial material preparation technology. The epitaxial wafer comprises, from bottom to top, a silicon carbide substrate, a β-Ga2O3 carbon getter layer, and a β-Ga2O3 drift layer. The carbon concentration ratio of the β-Ga2O3 carbon getter layer to the β-Ga2O3 drift layer is not less than 100, forming a decreasing carbon concentration gradient. The β-Ga2O3 drift layer contains periodically distributed annealing repair interfaces. The preparation method employs a precursor spatiotemporal separation alternating gas supply mode to grow the β-Ga2O3 drift layer, with periodic insertion of in-situ flash annealing steps. A three-stage carbon purification mechanism synergistically removes carbon from three stages: carbon source generation, defect complex formation, and cumulative stabilization, solving the technical bottleneck of uncontrollable carrier compensation ratio caused by organometallic precursor carbon contamination during MOCVD growth of ultra-thick drift layers.

This invention discloses a method for preparing magnesium-aluminate spinel transparent ceramics by hot-pressing sintering based on mold isolation technology, belonging to the field of transparent ceramics technology. The method involves setting an isolation layer between a graphite mold and a ceramic blank; wherein the isolation layer includes a graphite paper substrate and a homogeneous isolation layer disposed on one side of the graphite paper substrate, the homogeneous isolation layer being made of the same material as the ceramic blank. The isolation layer of this invention effectively blocks the diffusion of carbon-active substances released from the graphite matrix under high temperature and pressure into the ceramic blank, thereby significantly reducing the penetration and residue of carbon impurities inside the ceramic. This method achieves physical isolation by addressing the contamination propagation path, effectively suppressing carbon contamination in transparent ceramics at a lower cost without significantly altering the existing main process, and helps improve the optical uniformity, transmittance, and long-term reliability of the product.