Glass wafers are the circular pieces of precision glass which are used in numerous technical and industrial applications for high tech processing. Each wafer is subjected to a highly controlled inspection process using the precision laser measuring equipment to gauge the total thickness variations. To ensure that it is within the accepted tolerances this is crucial. Many high tech companies offers complete SIC (silicon carbide) wafer, or say, SIC wafer, substrate production line which can integrate crystal growth, crystal processing, wafer processing, polishing, cleaning and testing within the production line in house, making the whole production process more efficient.
There are many suppliers who offer commercial 4H and 6H SIC wafers with semi insulation and conductivity in the on-axis or off-axis options, with the available size ranging from 5x5mm2, 10x10mm2, 2”,3”,4” and 6” options. This scale range field has broken through certain key technology levels such as defect suppression, seed crystal processing and rapid growth ratio, and can thus promote basic and fundamental research and development related to the silicon carbide epitaxy substances as well as the related high tech devices.
In the field of chemistry and industry, the term epitaxy could refer to a type of crystal growth or material deposition by which new crystalline layers are formed with a well defined orientation. This orientation is planned with respect to the crystalline substrate as it is formed. This new layers formed are called the epitaxial film or epitaxial layer in the common usages by workers and engineers. The relative orientation of the epitaxial layer to the crystalline substrate is thus classified and defined in terms of the orientation of the crystal lattice of each material object and substance in this professional field of works.
The new layer will be crystalline and will all have a single orientation which is relative to the substrate, while the amorphous growth or multi crystalline growth with random crystal orientation does not meet this criterion standard for a series of reasons. Among the various field works, one of the primary commercial applications of epitaxial growth is in the semiconductor industry.
In the semiconductor sector the semiconductor films are grown epitaxially on semiconductor substrate wafers. In the case of epitaxial growth of a planar film atop of a substrate wafer, the result is positive indeed as the epitaxial film's lattice is going to have a specific orientation. The orientation is relative to the substrate wafer's crystalline lattice. The lattice cases are things such as the 001 Miller index of the film aligning with the 001 index of the substrate.
For the industrial usages in the simplest case with the simplest examples, the epitaxial layer can be a continuation of the same exact semiconductor compound material as the substrate substances. This is referred to as homo epitaxy for professional term usages in application. Otherwise, the epitaxial layer would be composed of different compound materials. This is referred to as hetero epitaxy material.
In the industrial usages, there are several different types of epitaxy types in the market, and this article will mention five of them for short introductory guides for a simple illustration here. The first one is the homo epitaxy, which is a kind of epitaxy which is performed with only one material. This mono material with a crystalline film is grown on a substrate or film of the same material unit. This technology is adopted to grow a film which is more pure than the substrate and to fabricate layers. The layers have different doping level options. In some academic literature, homo epitaxy, or homoepitaxy, is often abbreviated to homoepi for short usages.
The second is the famous homotopotaxy. This term means a industrial process which is similar to homoepitaxy. But the whole process is excluded with that the thin film growth is not limited to two dimensional growths. The substrate is the thin film material per se. After this one, here comes the third type of materials, which is called heteroepitaxy.
The substance heteroepitaxy is a type of epitaxy which is performed with materials that are different from others. In the case of heteroepitaxy, a crystalline film grows on a crystalline substrate of a different substance. And this technology is usually utilized to grow crystalline films of materials, and the crystals cannot otherwise be gained and to fabricate integrated crystalline layers. Industrial application instances include silicon on things such as sapphire, gallium nitride on sapphire, aluminum gallium indium phosphide on gallium arsenide or diamond or iridium.
Aside from the three cases, it is the heterotopotaxy. This is a process similar to heteroepitaxy. There are many types of the wafer glasses in the industry and the related epitaxy materials introduced above shall be considered as the critical parameters for the usages of this kind of industrial applications.
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