China high purity quartz sand Manufacturers, Suppliers, Factory

Tantalum carbide coating is an important high-strength, corrosion-resistant and chemically stable high-temperature structural material with a melting point of up to 4273 °C, one of the several compounds with the highest temperature resistance. It has excellent high-temperature mechanical properties, resistance to high-speed airflow scouring, ablation resistance, and good chemical and mechanical compatibility with graphite and carbon/carbon composites. Therefore, in the epitaxial process of GaN LEDs and SiC power devices such as MOCVD, TaC coating has excellent acid and alkali resistance to H2, HCl, NH3, which can completely protect the graphite substrate material and purify the growth environment.

SiC substrate material is the core of SiC chip. The production process of the substrate is: after obtaining the SiC crystal ingot through single crystal growth; then preparing the SiC substrate requires smoothing, rounding, cutting, grinding (thinning); mechanical polishing, chemical mechanical polishing; and cleaning, testing, etc. Process

Currently, many semiconductor devices employ mesa device structures, which are predominantly created through two types of etching: wet etching and dry etching. While the simple and rapid wet etching plays a significant role in semiconductor device fabrication, it has inherent drawbacks such as isotropic etching and poor uniformity, which result in limited control when transferring small-sized patterns. Dry etching, however, with its high anisotropy, good uniformity, and repeatability, has become prominent in semiconductor device fabrication processes. The term “dry etching” broadly refers to any non-wet etching technology used for removing surface materials and transferring micro and nano patterns, including laser etching, plasma etching, and chemical vapor etching. The dry etching discussed in this text specifically pertains to the narrow application of processes using plasma discharge—either physical or chemical—to modify material surfaces.

The fabrication of semiconductor devices primarily encompasses four types of processes: (1) Photolithography (2) Doping Techniques (3) Film Deposition (4) Etching Techniques The specific techniques involved include photolithography, ion implantation, rapid thermal processing (RTP), plasma-enhanced chemical vapor deposition (PECVD), sputtering, and both dry and wet etching methods.

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).

Defect-free epitaxial growth occurs when one crystal lattice has nearly identical lattice constants to another. Growth happens when lattice sites of the two lattices at the interface region are approximately matched, which is possible with a small lattice mismatch (less than 0.1%). This approximate matching is achieved even with elastic strain at the interface, where each atom is slightly displaced from its original position in the boundary layer. While a small amount of strain is tolerable for thin layers and even desirable for quantum well lasers, the strain energy stored in the crystal is generally lowered by the formation of misfit dislocations, which involve a missing row of atoms in one lattice.