The Spatial Distribution of Defects and Its Dependence on Seed Polarity and Off-Orientation during Growth of 4H-SiC Single Crystals
The defect distribution in 4H-SiC single crystals in dependence on the seed polarity and its off-orientation was investigated by KOH-etching, optical microscopy and X-ray topography. Micropipe density, stacking fault density and dislocation density were determined for 2” crystals grown in <000-1> direction 0 - 7° off towards <11-20> and for crystals up to 1” in diameter grown in <11-20> or a- and <1-100> or m-directions and using repeated a-face growth. For the growth in polar directions the micropipe density and dislocation density decrease with increasing offorientation of the seed. A similar behavior was found for the stacking fault density and dislocation density in non-polar directions with off-orientation to c-direction. Nevertheless, while the dislocation density could be reduced up to three orders of magnitude for the growth along non-polar directions, the stacking fault density was continuously increasing. Additionally, the defect distribution after repeated a-face growth will be discussed in terms of growth related and kinetic models.
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
H. J. Rost et al., "The Spatial Distribution of Defects and Its Dependence on Seed Polarity and Off-Orientation during Growth of 4H-SiC Single Crystals", Materials Science Forum, Vols. 527-529, pp. 9-14, 2006