Epitaxial wafers are the traditional wafers to achieve surface integrity by putting various thickness epitaxial silicon layers. Thin Epi wafers are commonly used for leading edge MOS devices. Thick Epi or Multi-layered epitaxial wafers are used for the devices mainly to control electric power, and they are contributing to improving the efficiency of energy consumption.
COP (Void, grown-in defect)
BMD (oxygen precipitate)