Epitaxial silicon wafers

Epitaxial Silicon Wafers using Plasma-Enhanced, Chemical-V apor-Deposition... 

When classifying chemical products, Seider et al. [3] identify three categories (1) basic chemicals (commodity and specialty chemicals, bio-materials, and polymeric materials) (2) industrial chemicals (films, fibers, paper,. ..) and (3) configured consumer products (dialysis devices, post-it notes, transparencies, drug delivery patches,. ..). In the manufacture of epitaxial silicon wafers, a thin film of crystalline silicon is often deposited on a polished crystalline silicon... 

Epitaxial Silicon Wafers using Plasma-enhanced Chemical-Vapor-Deposition 291... 

Using a 260/wafer sales price for epitaxial silicon wafers and the United States MACRS tax-basis depreciation schedule, the investor s rate of return (IRR) is 18.3%. In addition, the return on investment (ROI) is 25.3%. These measures increase significantly with small changes in sales price for example, at 273/wafer, the IRR is 29.9%. Note that the economic analysis is somewhat shielded from variations in the price of epitaxial wafers because it is strongly linked to the price of the incoming polished wafers. In other words, the key metric of interest is the value added to the wafer by the epitaxial film deposition. 

For epitaxial silicon wafers, product design focuses on optimizing the geometry of the plasma-enhanced, chemical-vapor-deposition (PECVD) reactor. To increase productivity, and maintain acceptable thickness uniformity, on the order of 5%, a simple optimization strategy locates a design that completes the deposition in 62 s. Then, for a standard manufacturing process, the economics are driven by the wafer costs, which are provided by a vendor at 206/wafer. At a sales price of 260/epitaxial wafer, the investor s rate of return is 18.3% and the return on investment is 25.3%. 

D. A. Brass and A. G. Lee, The Production of Epitaxial Silicon Wafers via Plasma Enhanced Chemical Vaposition, Univ. Pennsylvania, Towne Library, 2003. 

As the density of devices placed on the silicon wafer increases, the problems of autodoping and interdiffusion become more acute and the high temperature limitation of the above reactions has prompted much experimental effort to develop epitaxial deposition at lower temperature. This has been accomplished in the following experimental developments ... 

Epitaxial thin films of silicon, to be deposited on crystalline silicon wafers, require no materials development. Other semi-conductor materials are possible, but silicon continues to be most cost-effective, principally due to the relatively... 

Details of building specific types of microelectronic devices are well described by Grovenor15 as an illustration, we consider only the chemical techniques involved in making a metallic contact to a silicon wafer surface. Preparation of a wafer of Si or other material and application of epitaxial layers of semiconducting or insulating materials, if required, were outlined in Section 19.2.1. The construction of shaped features on the wafer is usually done by photolithography, or ion- or electron-beam variants thereof. 

The liquid solution CCVD process does not deposit droplets (these evaporate in the flame environment) or powders as in traditional thermal spray processes. The CCVD technology is drastically different from spray pyrolysis In spray pyrolysis, a liquid mixture is sprayed onto a heated substrate, while CCVD atomizes a precursor solution into sub-micron droplets followed by vaporization of said droplets. The resulting coating capabilities and properties described hereafter qualifies CCVD as a true vapor deposition process. For example, depositions are not line-of-sight limited and achieve epitaxy, 10 nm dielectric coatings onto silicon wafers in a Class 100 clean room resulted... 

This is used to produce epitaxial silicon on semiconductor silicon wafers. 

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