Silicon wafers are thin, circular discs made of high-purity silicon that are used in the fabrication of semiconductor devices such as microchips. They are typically used as the substrate on which microelectronic devices are built, and they can be purchased from a variety of sources, including online retailers and specialized manufacturers. When purchasing silicon wafers, it is important to consider factors such as the diameter and thickness of the wafers, the type of silicon used (such as single-crystal or polycrystalline), and the surface finish (such as polished or epi-ready). It is also important to consider the level of purity required for your application, as the purity of the silicon can affect the performance of the devices built on the wafer. Finally, you should be aware of any specific requirements or specifications that your application may have, such as the need for particular dopants or a certain level of flatness.