Helix Dislocations

Screw dislocations can climb, too. As a result they turn into a helix; a real "screw". The segments finally may collapse into a system of coaxial dislocation loops.
The images show screw dislocations in the emitter area of bipolar transistors in an early and advanced stadium of climb (right and center) and the final collapse into dislocation loops.
helix dislocations

With frame With frame as PDF

go to 5.3.2 Climb of Dislocations

go to 6.3.2 Examples and Case Studies for Dislocations

go to 6.3.3 Stacking Faults and Other Defects

© H. Föll (Defects - Script)