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CRYSTAL GROWTH TECHNIQUES

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SHASHI SHAW
SHASHI SHAW

This document discusses techniques for growing silicon single crystals, specifically the Bridgman and Czochralski (CZ) techniques. It provides details on the process and equipment used for each technique. The CZ technique is considered preferable for growing silicon single crystals over the Bridgman technique. CZ crystals have fewer dislocations and allow for better control over the crystal growth process and ambient conditions compared to Bridgman. While more complex, CZ produces higher quality silicon single crystals.

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PRESENTED BY:- SHASHI KUMAR SHAW 2K13E25 UNIVERSITY OF PUNE
Introduction Types of crystal growth Bridgeman technique CZ technique Conclusion
Silicon is a most abundant material is nature It contents many impurities Defects in crystal Single crystal is the requirement
1. Bridgman technique 2. Czochralski technique But CZ is most preferable technique for the growth of single crystal silicon over Bridgman.
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
Si melt Si
Bridgman growth single crystal have a lot of dislocation
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
CRYSTAL GROWTH TECHNIQUES
L dm dt k L dT dx 1 A1 k S dT dx 2 A2 L latent heat of fusion dm dt amount of freezing per unit time kL thermal conductivity of liquid dT dx1 thermal gradient at isotherm x1 kS thermal conductivity of solid dT dx 2 thermal gradient at x 2
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.
Bridgman crystal growth technique is simple but with serious limitation. CZ is complex process but it give good quality of single crystal than Bridgman.
CRYSTAL GROWTH TECHNIQUES
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CRYSTAL GROWTH TECHNIQUES

  • 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
  • 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 k L dT dx 1 A1 k S dT dx 2 A2 L latent heat of fusion dm dt amount of freezing per unit time kL thermal conductivity of liquid dT dx1 thermal gradient at isotherm x1 kS thermal conductivity of solid dT dx 2 thermal gradient at x 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.