This document summarizes the key steps in integrated circuit fabrication: 1) wafer preparation through crystal growth, 2) oxidation, 3) photolithography, 4) diffusion, 5) ion implantation, 6) metallization, 7) testing, 8) passivation, and 9) packaging. It describes processes like Czochralski growth, oxidation, photolithography, diffusion, ion implantation, and metallization. It also discusses semiconductor types, apparatus used, and differences between diffusion, ion implantation, and doping. The document provides an overview of IC fabrication methods and processes.

1. IC FABRICATION
BY
BHAVANA.POTTURI

2. STEPS
1.Crystal growth(wafer preparation)
2.Oxidation
3.Photo lithography
4.Diffusion
5.Ion implantation
6.Metallization
7.Testing
8.Passivation
9.Packaging
Ic is ready

3. TYPES OF SEMI CONDUCTOR
1.PURE SEMI CONDUCTOR
2.INTRENSIC SEMI CONDUCTOR
3.EXTRENSICSEMI CONDUCTOR

4. WAFER FABRICATION
Czochralski process

5. APPARATUS

6. OXIDATION
Why oxidation is required?
Types of oxidation
1.Dry oxidation @1200⁰c
It is very slow process :si+O₂sio₂
2.Wet oxidation@1000⁰c
It is very rapid process :si+2H₂0SIO₂+2H₂

7. PHOTO LITHO GRAPHY
LIGHT STONE PICTURE 1.PHOTO RESIST
2.PHOTO MASK
3.ETCHING
TYPES OF LITHOGRAPHY
1.POSITIVE PHOTO LITHOGRAPHY
2.NEGATIVE PHOTO LITHOGRAPHY

9. DIFFUSION
P- TYPE
B₂O₃,BCl₃
N –TYPE
P₂0₅

10. ION IMPLANTATION

11. DIFFERENCE BETWEEN DIFFUSION
AND ION IMPLANTATION AND DOPING
Doping is adding atoms to a material to modify the conduction properties, for example
to make an N type conductor or a P type conductor.
Diffusion is allowing atoms of one material to move by heating it enough that the atoms
can move to other positions. One can dope silicon by putting arsenic (or other dopants)
on the silicon surface, and putting the silicon wafer in an oven at a temperature that
allows the arsenic atoms to diffuse (or move) into the silicon and modify the conduction
properties. By choosing the proper temperature and diffusion time it can be possible to
control the depth and concentration of the arsenic in a way that is useful for making a
desired semiconductor device.
Ion implantation is making a beam of energetic ions and allowing them to hit a surface
made of some material -- a material different from the ions. It is used to modify the
properties of the material being bombarded. It can also be used to dope
semiconductors. The high energy of the ions can damage the lattice structure that is
being doped, so it is usually necessary to anneal the semiconductor by heating to allow
it to "heal itself". Ion implantation can also be used to harden metal surfaces or change
their friction properties by choosing the right type of ions to implant.

12. METALLIZATION
WORK FUNCTIONS
OHMIC CONTACTS
RECTIFYING CONTACTS
1.Filament Evaporation
2.Flash Evaporation
3.Electron-beam Evaporation
4.Sputtering

13. TESTING

14. PASSIVATION
PACKAGING

15. Example:nmos fabrication

18. Why gallium arsenide?
• High Electron Mobility High Electron Mobility
– High frequency operation
• Intrinsic GaAs is Semi Intrinsic GaAs is Semi-
Insulating Insulating
– Well suited for use as a substrate
for stripline and passives for stripline and
passives
– High Q
• Large Band Gap 1 4eV Large Band Gap 1.4eV
– High voltage = higher power
– Radiation hard

21. EPI-TAXIAL GROWTH
ON ARRANGEMENT
TYPES OF EPITAXY
1.VAPOUR PHASE EPITAXY
2MOLECULAR –BEAM EPITAXY
3LIQUID-PHASE EPITAXY

22. MESFET

23. Any queries?
FEEDBACK