High-Efficiency Conversion of Threading Screw Dislocations in 4H-SiC by Solution Growth

Abstract

The high-efficiency conversion of threading screw dislocations (TSDs) in 4H-SiC by solution growth provides an efficient method of obtaining ultra high-quality SiC crystals. The behavior of TSDs on on-axis and off-axis 4H-SiC{0001} seed crystals was investigated by synchrotron X-ray topography. Almost all TSDs in the off-axis Si-face seed crystal were converted to Frank-type stacking faults on the basal planes. The conversion ratio of TSDs was highly influenced by the surface polarity of the seed crystal. The stacking faults laterally propagate toward the outside of the crystal. #

Effect of aluminum addition on the surface step morphology of 4H–SiC grown from Si–Cr–C solution

“…Recently, the study of solution growth has rapidly developed, and it has attracted interest as a growth method for high-quality SiC crystals [1][2][3][4][5][6][7]. Several studies have reported significant reduction of threading dislocations during crystal growth [2][3][4][5]. Threading dislocations convert to defects on basal (0001) planes by the interaction between the dislocations and macrostep flow during growth [2][3][4].…”

Evolution of threading screw dislocation conversion during solution growth of 4H-SiC

“…During the solution growth of SiC, highly efficiency TSD conversion has been reported. 7 In this case, over 99% of the TSDs were converted to the extended defects on the basal planes within 10 μm growth.…”

“…Recently, we have revealed that TSDs are converted to defects on the basal planes propagating to the step-flow direction during the solution growth on vicinal seed crystals of SiC(0001). [7][8][9] The conversion leads to the reduction of TSD density because the converted defects laterally extend toward the outside. However, the detail of the dislocation evolution during the solution growth is still not clear.…”

“…The macrosteps formed on the growth surface have been reported to be attributed to the threading dislocation conversion. 7,17,18 Lateral growth of macrosteps would lead to the TSD conversion during the solution growth of SiC. 7 Figure 3 shows the X-ray topography image of the seed crystal and the grown crystal taken at the same position.…”

“…The knife-shaped contrasts were reported to represent the extended defects on the basal planes which were reported to be composed of 4 Frank partial dislocations each having 1/4[0001] Burgers vector with stacking faults on the (0001) basal plane between them. 7,19,20 In the topography image of the grown crystal taken under the condition #3 [ Fig. 3(c)], the TSDs (A and B ) in seed crystal as well as the extended defects on the basal planes (C and D ) in the grown layer were simultaneously recorded.…”