Dislocation Reactions in Silicon Web-Dendrite Crystals

Abstract

The origin and reactions of dislocations in silicon web-dendrite crystals are discussed. In particular, x-ray topographs are compared with etching results. Dislocations having [21̄1̄] axes or 〈110〉 type axes have been characterized. In the former case, normal edge and 20° dislocations are seen; however, an apparently new dislocation with a [21̄1̄] axis and [101] type or [110] type of Burgers vector has also been observed. Dislocations having a [11̄0] axis and [110] Burgers vector have been identified and associated with the Cottrell-Lomer reaction. The presence of multiple twin planes parallel to the growth direction of the web, accompanied by regions of very high dislocation density near the dendrites, increases the probability of certain dislocation reactions.

Growth of Wide, Flat Crystals of Silicon Web

“…In our web, the majority of dislocations were generated in bursts at melt e n t r a p m e n t centers on the dendrite surfaces (4,7). In our web, the majority of dislocations were generated in bursts at melt e n t r a p m e n t centers on the dendrite surfaces (4,7).…”

“…Dec. 15, 1970. This was Paper 513 presented at the Montreal Meeting of the Society, Oct. [6][7][8][9][10][11] 1968.…”

“…Greater width is desirable, for many power devices are larger than 1 cm in diameter and, while large-area rectangular-shaped web was available, this shape is not compatible with present industry tooling. In addition, photomasking requires a surface flat to 10 ~m, and, although web in thin section has been reported within this tolerance (7), many devices require a thicker substrate material. Finally, dislocations which generate in the supporting dendrites accumulate within thicker web during growth (4, 7), often reaching densities of 103-105 dislocation pits/cm 2.…”

Electron Microscopy of WEB‐Dendritic Silicon

“…The defect structure was previously investigated by etching and x -r a y topographical techniques (5,6). This paper reports on an extensive investigation by electron microscopy using a high voltage transmission electron microscope (accelerating voltage V = 1 MV) and a scanning electron microscope (V = 1 1 .…”

Electron Microscopy

“…Wilhelm and Joshi (639) reported that fault planes in steam oxidized silicon appeared to be due to oxygen induced precipitation along faults producing strain displacement fields which give rise to dislocations during the steam oxidation treatment. The origin and reactions of dislocations in silicon and germanium were discussed by O'Hara (438) and O'Hara and Schwuttke (439). The effects of dislocation interactions in silicon were made visible by the peculiar etching characteristics of the dislocations involved.…”