Wafer

In gastronomy, a wafer is a crisp, often sweet, very thin, flat, and dry biscuit, often used to decorate ice cream. Wafers can also be made into cookies with cream flavoring sandwiched between them. They frequently have a waffle surface pattern but may also be patterned with insignia of the food's manufacturer or may be patternless. Many chocolate bars, such as Kit Kat and Coffee Crisp, have wafers in them.

Communion wafer

The word also refers to the special small round, often starchy flatbreads made for Western Rite celebrations of the Eucharist, including Roman Catholic, Anglican, Lutheran and some of the more liturgical Protestant churches. The word "host" is used to describe the larger wafer used by the clergy, while the term "communion wafer" refers to the smaller pieces used to distribute Holy Communion to the people. These holy wafers often have an image of a cross or the crucified Christ imprinted on them.

Spa wafers

Special "spa wafers" (Czech: lázeňské oplatky, Slovak: kúpeľné oblátky) are produced in the spa towns of the Czech Republic (e.g. Karlovy Vary, Mariánské Lázně, etc.) and the Slovak Republic (e.g. Piešťany, etc.).

Wafer (surname)

Wafer (Weafer, Weaver) is an English surname, and may refer to

See also

Wafer (electronics)

A wafer, also called a slice or substrate, is a thin slice of semiconductor material, such as a crystalline silicon, used in electronics for the fabrication of integrated circuits and in photovoltaics for conventional, wafer-based solar cells. The wafer serves as the substrate for microelectronic devices built in and over the wafer and undergoes many microfabrication process steps such as doping or ion implantation, etching, deposition of various materials, and photolithographic patterning. Finally the individual microcircuits are separated (dicing) and packaged.

History

By 1960, silicon wafers were being manufactured in the U.S. by companies such as MEMC/SunEdison. In 1965, American engineers Eric O. Ernst, Donald J. Hurd, and Gerard Seeley, while working under IBM, filed Patent US3423629A for the first high-capacity epitaxial apparatus.

Formation

Wafers are formed of highly pure (99.9999999% purity), nearly defect-free single crystalline material. One process for forming crystalline wafers is known as Czochralski growth invented by the Polish chemist Jan Czochralski. In this process, a cylindrical ingot of high purity mono crystalline semiconductor, such as silicon or germanium, called a boule, is formed by pulling a seed crystal from a 'melt'. Donor impurity atoms, such as boron or phosphorus in the case of silicon, can be added to the molten intrinsic material in precise amounts in order to dope the crystal, thus changing it into n-type or p-type extrinsic semiconductor.