270201 Observations, Formation Mechanisms and Reduction Methods of 3-Dimensional Cross-Slip Dislocations in Silicon Single Crystal

Thursday, November 1, 2012: 1:50 PM
Westmoreland East (Westin )
Do Won Song, Sapphire Business Team, LG Siltron, Gyeonggi-do, South Korea and Hyo Kim, University of Seoul, Seoul, South Korea

New crystalline defects in silicon single crystal are discovered. We have observed the defects using by scanning electron microcope (SEM), atomic force microscope (AFM), transmission electron microscope (TEM), scanning infrared depolarization (SIRD) and etching method. It is founded that new defects are three dimensional screw lines propagating 8-degree tilted <100> direction. We have examined the effects on the gate-oxide insulation (GOI) by them and founded that A- and B-mode failure are happened. It reveals that the defects have affected directly a fault of semiconductor device and should be removed or at least reduced. Also, we have studied the formation mechanisms using the generalized Gibbs-Thomson theory. Due to application of a strong magnetic field, the horizontal magnetic Czochralski (HMCZ) method has a disadvantage of immiscible fluid characteristics. On the other hand, an ingot grown from a single crystalline seed and a crucible each has rotated at a predetermined speed. Thus, the spiral shear distortions have happened on the crystallization front (CF) surface bewteen grown crystal and immiscible melt. As existing the spiral shear distortions, it is possilble that the CF could propagated by not two-dimmensional nucleation method but screw-dislocation method during the crystallization process. Because of a difference between CF and three-dimensional arrangement of Silicon atoms, the screw dislocations have developed into jogged screw dislocations and propagated by climbing to form cross-slips during thermal process wherein a crystal cooled. Therefore, we have named the newly generated defects in a Silicon single crystal as a cross-slip dislocation (CSD). And to reduce the CSD, we newly have proposed an apparatus included an upper heat shield structure that is spaced apart with a predetermined gap from a surface of a silicon melt contained a crucible and arranged around a silicon single crystalline ingot pulled from the silicon melt. And we have experimentally showed that the CSD have been decreased remarkably by changing the initial conditions, operational conditions and cooling method using the newly designed apparatus. Therefore we could say that proposed formation mechanisms are appropriate.

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