| About this Abstract |
| Meeting |
2011 Electronic Materials Conference
|
| Symposium
|
2011 Electronic Materials Conference
|
| Presentation Title |
K6, Deflection of Threading Dislocations with Burgers Vector c/c+a Observed in 4H-SiC Substrates and Axial Slices with Associated Stacking Faults |
| Author(s) |
S. Byrappa, F. Wu, H. Wang, B. Raghothamachar, G. Choi, S. Sun, M. Dudley, E.K. Sanchez, D. Hansen, R. Drachev, S.G. Mueller, M.J. Laboda |
| On-Site Speaker (Planned) |
S. Byrappa |
| Abstract Scope |
From its inception SiC has attracted lot of attention due to its superior properties compared to conventional semiconductor materials, but the high defect density and its implications on device performance have precluded it from being used on a large commercial scale. Here Synchrotron White Beam X-ray Topography(SWBXT) studies have been presented of threading dislocations with Burgers vector c and c+a, which get deflected onto the basal plane by the overgrowth of a macrostep. These deflected dislocations in turn produce stacking faults with different fault vectors. Three different stacking faults have been observed in SiC to date: Shockley faults, Frank faults and those comprising a combination of these two. First, Shockley faults are known to be caused by the expansion of dissociated Si- and C- core partials, whose existence in SiC has been explained due to its low stacking fault energy. Secondly, Frank faults have been considered to be “in-grown” stacking faults and are thought to result from overgrowth of c-axis screw dislocations. Lastly, a combination of Frank and Shockley faults with fault vectors 1/12<4-403> have been previously observed although no model was presented to explain this phenomena. Dudley et al [1] recently have reported the mechanism for their formation which is due to the deflection of threading dislocations of different Burgers vector onto the basal plane and the simultaneous dragging of the BPD partials pinned at their cores resulting in large stacking faults. These faults arise when dislocations with Burgers vector c+a protrude onto the terrace created by deflection of c-axis screw dislocations, whose surface growth spiral steps are separated into c/4, c/2 and 3c/4 step heights and by the simultaneous growth of macrostep at this juncture. The model for deflection of threading dislocations with Burgers vector n[0001] and 1/3<11-23> type along with the formation mechanism of stacking faults with fault vectors 1/12<40-43> will be discussed in greater detail. Topographic evidence will also be provided for the presence of c+a dislocations from slices cut parallel to the growth axis, which was only postulated for many decades but not observed in SiC until recently. |
| Proceedings Inclusion? |
Undecided |