Scene 1

Scene 2

Discussed different defects that could occur on a Semiconductor.

Scene 3

All semiconductors contain defects. They may be foreign atoms (impurities) or crystalline defects.  Impurities are intentionally introduced as dopant atoms (shallow-level impurities), recombination centers (deep-level impurities) to reduce the device lifetime, or deep-level impurities to increase the substrate resistivity.  Impurities are also unintentionally incorporated during crystal growth and device processing.

Scene 4

Point Defect Foreign Interstitial Foreign substitutional Line Defect Edge Dislocation Screw Dislocation Surface Defect Grain Boundary Twin Boundary Volume Defect Void Crack Inclusion Precipitate

Scene 5

It is formed when a foreign atom is positioned in the crystal structure at a point that is normally unoccupied. The defect is formed when a solute atom such as an alloying or impurity sits within a gap between the crystal lattice points of the base metal (solvent).

Scene 6

Interstitial Atom - an overview | ScienceDirect Topics

An interstitial defect is often formed in metal alloys when the size of the solute atom is less than about 85% of the size of the host metal atom. This defect may not have great effect on the overall functionality of an Integrated Circuit but may cause degradation on the performance through time.

Scene 7

Effect : Small leakage current on the source terminal.

Scene 8

It occurs when the original atom in the lattice site of a crystalline solid is replaced by a different type of atom. Unlike interstitial defect, foreign atom should occupy the lattice site only and not the interstitial position, as depicted on the diagram.

O
e e eoe
O
O
Perfect Crystal
e e eoe
ooeoo
SulFtitutional Atom - Point

Scene 9

Where Substitutional defects can be found?

Substitutional defects can be found in brass, where zinc atoms replace copper atoms. In semiconductor materials also.

Scene 10

Causes and Effects of Substitutional defects

Presence of foreign atoms as natural impurities within the solid. Deliberate addition, such as during iron to steel conversion, heat treatment, sputtering, etc. Diffusion, caused by close contact between two different materials.

Presence of substantial number of foreign atoms can change the mechanical and thermal properties of the solid. However, this is sometime beneficial, and thus substitutional defects can be applied in a controlled way to enhance various properties of the solid. Presence of foreign atom may distort the original lattice structure. If the foreign atom is smaller in size as compared to the original atom of the solid, the neighboring atoms will remain in tensile stress. If the foreign atom is larger in size as compared to the original atom of the solid, the neighboring atoms will remain in compressive stress.

Scene 11

Effect : High resistance on the source terminal or open-circuit.

Scene 12

An edge dislocation is a defect where an extra half-plane of atoms is introduced mid way through the crystal, distorting nearby planes of atoms.  It is also called as Taylor- Orowan  dislocation. It will have regions of compressive and tensile stresses on either side of the plane containing dislocation.

Region of compression
Region og tension
Posiåve Edge dislocation
Negafr.,'e Edge dislocation

Scene 13

Effect : High current consumption on the gate terminal.

Scene 14

It is also called as Burger’s dislocation. It will have regions of shear stress around the dislocation line.

Scene 15

Effect : Results to weak SiO2 on the gate terminal that may lead to high leakage current.

Defects

Page 1 (0s)

Page 2 (7s)

Page 3 (15s)

Page 4 (44s)

Page 5 (1m 14s)

Page 6 (1m 35s)

Page 7 (1m 55s)

Page 8 (2m 18s)

Page 9 (2m 45s)

Page 10 (3m 0s)

Page 11 (4m 7s)

Page 12 (4m 32s)

Page 13 (4m 54s)

Page 14 (5m 16s)

Page 15 (5m 27s)