This document discusses and compares two techniques for growing single crystal silicon: the Bridgman technique and the Czochralski (CZ) technique. It states that while the Bridgman technique is simpler, involving a quartz ampoule, boat, heater and temperature profile, crystals grown with this method contain many dislocations. The CZ technique is more complex but can produce higher quality crystals. It involves controlling a furnace, crystal pulling rate, ambient conditions and system. The document concludes that the CZ technique is preferable for growing single crystal silicon due to producing crystals with fewer defects.

1. PRESENTED BY:-
SHASHI KUMAR SHAW
2K13E25
UNIVERSITY OF PUNE

2.  Introduction
 Types of crystal growth
 Bridgeman technique
 CZ technique
 Conclusion

3.  Silicon is a most abundant material is nature
 It contents many impurities
 Defects in crystal
 Single crystal is the requirement

4. 1. Bridgman technique
2. Czochralski technique
But CZ is most preferable technique for the
growth of single crystal silicon over Bridgman.

5.  It is a very simple process
System for Bridgeman :-
1. Quartz ampoule
2. Quartz boat
3. Seed crystal
4. Charges
5. Heater
6. Temperature profile

6. Si melt
Si

7.  Bridgman growth single crystal have a lot of
dislocation

8.  CZ is also known as “liquid solid
monocomponent growth system”
 CZ is more complex than Bridgman
Requirement for CZ:-
1. Furnace
2. Crystal pulling rate
3. Ambient control
4. Control system

10. L
dm
dt
 kL
dT
dx 1
A1  kS
dT
dx 2
A2
L latent heat of fusion
dm
dt
 amount of freezing per unit time
kL  thermal conductivity of liquid
dT
dx 1
 thermal gradient at isotherm x1
k thermal conductivity of solid
S dT
 thermal gradient at x 2
dx 2

11.  Reaction of O2 with single crystal silicon during
growth it alters the properties of grown silicon.
 95% O2 will be in interstitial sites in the crystal
 5% can form a complex impurity like SiO4
(donor)
 If the O2 concentration > 6.4*10^17/cm3
dislocation will form in the crystal.

12.  Bridgman crystal growth technique is simple
but with serious limitation.
 CZ is complex process but it give good quality
of single crystal than Bridgman.

14. THANK YOU