Skip to main content Accessibility help

X-Ray Investigation of a 2H-3C Phase-Transformation in Silicon Carbide Single Crystals

  • P. Krishna (a1) and R. C. Marshall (a1)


This paper reports the results of a detailed X-ray diffraction study of a new phase-transformation observed in SiC crystals grown by a vapour-liquid-solid mechanism involving the hydrogen-reduction of methyltrichlorosilane. The 10.ℓ reciprocal lattice rows of these crystals, as recorded on X-ray diffraction photographs, reveal sharp reflections corresponding to the hexagonal close-packed 2H (ABAB….) structure and sometimes also corresponding to the cubic close-packed 3C (ABCABC…) structure. These reflections are invariably connected by a diffuse but continuous streak whose intensity is a measure of the random faulting on the basal planes. The crystals were needle shaped and the structure sometimes varied along their length.

Several crystals were annealed in an inert atmosphere at progressively higher temperatures and their 10.ℓ reciprocal lattice row re-examined to determine the annealing behaviour as well as possible structural transformations. For a number of dark green needles having a faulted 2H structure the 2H reflections disappeared around 1400° C and the 10.ℓ reciprocal lattice row revealed only a continuous streak with increased intensity around positions for 3C reflections. On further heating the structure went over to a strongly faulted 3C. Around 1600°C the appearance of a 6H structure became discernible while highly diffuse 30 reflections still persisted. The reversible part of the transformations, if any, could not be observed. Some of the structures were, however, found to be much more stable and did not transform even up to 1650° C.

The above results, in particular the discovery of a 2H-3C phase-transformation around 1400°C, throw fresh light on the thermodynamic stability of the different SiC types. The mechanism of the 2H-3C transformation, the possible influence of faults and impurities and the thermal stability of various SiC structures are discussed on the basis of the experimental results stated above.



Hide All
1. Verma, A. R. and Krishna, P., Polymorphism and Polytypism in Crystals, Wiley (1966). Russian translation , Editor, Povarennykh, A. S., MIR Publishing House, Moscow (1969).
2. Baumann, H. N. Jr., “The Relation of Alpha and Seta Silicon Carbide,” J. Electrochem. Soc. 99, 109114. (1952).
3. Adamsky, R. F. and Merz, K. M., “Synthesis and Crystallography of the Wurtsite Form of Silicon Carbide,” Z. Krist. 111, 350361 (1959).
4. Knippenberg, W. F., “Growth Phenomena in Silicon Carbide,” Philips Res. Rept. 13, 161274. (1963).
5. Griffiths, L. B., “Defect Structure and Polytypism in SiC,” J. Phys. Chem. Solids 27, 257266 (1966).
6. Weltner, W. Jr., “On Polytypism and Internal Rotation,” J. Chem. Phys. 51, 2469-2483 (1969).
7. Scace, R. I. and Slack, G. A., “Solubility of Carbon in Silicon and Germanium,” J. Chem. Phys. 30, 15511556 (1959).
8. Zhdanov, G. S., “The Numerical Symbol of Close-Packing of Spheres and its Application in the Theory of Close-Packings,” Compt. Rend. Acad. Sci. URSS 48, 43 (1945).
9. Patrick, L., Hamilton, D. R. and Choyke, W. J., “Growth, Luminescence, Selection Rules and Lattice Sums of SiC with Wurtzite structure,” Phys. Rev. 143, 526536 (1966).
10. Patrick, L., “High Electron Mobility of Cubic SiC,” J. Appl. Phys. 37, 49114913 (1966).
11. Ryan, G. E., Berman, I., Marshall, R. G., Considine, D. P. and tfewley, J. J., “Vapor-Liquid-Solid and Melt Growth of Silicon Carbide,” J. Crystal Growth 1, 255262 (1967).
12. Wagner, R. S. and Ellis, W. C., “Vapor-Liquid-Solid Mechanism of Single Crystal Growth,” Appl. Phys. Lett. 4, 8990 (1964).
13. Powell, J. A., “Crystal Growth of 2H Silicon Carbide,” J. Appl. Phys. 40, 4660-4662 (1969).
14. Knippenberg, W. F. and Verspui, G., “The Influence of Impurities on the Growth of Silicon Carbide Crystals Grown by Gas-Phase Reactions,” Mat. Res. Bull. 4, S33-S44 (1969).
15. Daniels, B. K., “The Phase-Change of ZnS and the Stacking Sequence of a New 66R Polytype,” Phil. Mag. 1£, 487500 (1966).
16. Mardix, S., Kalman, Z. H. and Steinberger, I. T., “Periodic Slip Processes and the Formation of Polytypes in ZnS Crystals,” Acta Cryst. A24, 464469 (1968).
17. Gomes de Mesquita, A. H., “Refinement of the Crystal Structure of SiC Type 6H,” Acta Cryst. 23, 610617 (1967).


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed