KOH etching and high-resolution X-ray diffractometry (HRXRD) were used to study the evolution and structure of low-angle grain boundaries (LAGBs), which extended along < 1 -1 0 0 > in 6H-SiC bulk crystals grown by the sublimation method. It was found that LAGBs formed in the growth process consisted of an array of threading dislocations and took different configurations under different radial temperature gradients (RTGs). HRXRD results proved that the domain at one side of LAGBs formed under a low radial temperature gradient has only tilts around the c-axis with respect to the other domain at another side of LAGBs. (C) 2010 Elsevier B.V. All rights reserved.