Polycrystalline silicon (PolySi), is a poly crystalline form of Si. It is high purity and is widely used in the manufacture of Photovoltaic (PV) devices .PolySi can be deposited using Plasma Enhanced Chemical Vapour Deposition (PECVD). It can be etched using Inductively Coupled Plasma (ICP) and Reactive Ion Etching (RIE).