Thin film deposition: Silicon wafer is placed in a deposition chamber, and the constituents of the film are delivered through the gas phase to the surface of the substrate where they form the film. There are two types of thin film deposition –

1. Physical Vapor Deposition (PVD) –

In this case physical methods are used to produce the constituent atoms which pass through a low-pressure gas phase and then condense on the substrate. It has two types

a) Evaporation – It is nothing but heating of a solid or molten source until it vaporizes.

b) Sputtering – Bombarding a solid source with energetic ions formed in a plasma is called sputter deposition.

2. Chemical Vapor Deposition (CVD) –

In this case, reactant gases are introduced into the deposition chamber, and chemical reactions between the reactant gases on the substrate surface are used to produce the film. It further has three types –

a) APCVD

b) LPCVD

c) PECVD