Silicon wafers are a key component of integrated circuits such as those used to power computers, cellphones, and a wide variety of other devices. A silicon wafer consists of a thin slice of silicon which can be treated in various ways, depending on the type of electronics it is being used in. Silicon is a very high quality semiconductor, making it ideal for the production of such circuits, although other materials have been explored historically. Much of the world's production of silicon wafers was historically centered in the aptly-named Silicon Valley in California.
If the development of the integrated circuit revolutionized human society, the silicon wafer deserves a big part of the credit. While other semiconductors were tested and tried, silicon proved to be the most stable and useful. Fortunately, the raw materials for silicon wafers are quite accessible, even if some work is required to produce wafer-grade silicon.
Making silicon wafers is a lengthy process. A lab must grow a silicon crystal in highly controlled conditions to maintain purity, although the lab may selectively dope the crystal with certain ingredients during the growth process. Once the crystal is grown, it is cut into thin slices which must then be polished before they can used to make integrated circuits.
A number of companies specialize in the production of silicon wafers. They sell wafers in a range of sizes for various applications, and can offer wafers which have been processed in specialized ways. The amount of doping can be critically important for certain types of projects. Levels of impurities introduced through doping may be acceptable for some applications, but not for others, which requires labs to have very tight quality control.
Components of an integrated circuit can be installed inside a silicon wafer, in addition to installed on or around it. The technology behind integrated circuits is constantly evolving, as people push to make smaller and better circuits. Developments in this technology tend to increase steadily, according to a prediction known as Moore's Law, although critics of Moore's Law have pointed out that the technology cannot improve infinitely, which means that a ceiling will be reached at some point.
The production of silicon wafers is not without controversy. The process generates a range of byproducts, some of which are hazardous. In the Silicon Valley, pollution as a result of chemicals released into the environment is a major problem in some areas, and companies which manufacture wafers are constantly looking for new ways to make the process cleaner and safer for the environment.