Micropipe-Like Defects in the Expanded Diameter Region of 8 in. SiC Grown by Physical Vapor Transport

Abstract

This study presents the growth of 8 in. silicon carbide (SiC) single crystals using a multiple-expanding diameter growth process via the physical vapor transport technique, with commercial 6 in. n-type SiC of 4° off-axis toward [11 0] as the seed. Micropipe-like defects were observed in the expanded diameter region, whereas they are absent in the unexpanded diameter region grown on the SiC seed via step-flow growth mode. Optical microscopy, scanning electron microscopy, micro-Raman spectroscopy, laser scanning confocal microscopy, defect-tracking experiments, and energy-dispersive spectroscopy were employed to investigate the morphology, polytype, and formation mechanism of the defects. The micropipe-like defects, with diameters in the dozens of micrometers scale and an angle ∼50° relative to the [000 ] direction, were found to stem from carbon particles decomposed from SiC powders. No other polytype inclusions were observed in these defects. By applying sintered SiC powders as starting materials, micropipe-like defects were effectively reduced. Our results provide an efficient method for growing large-size SiC single crystals of high-quality and low-defect density via the multiple-expanding diameter growth process.

Effect of TCS gas flow and pre-etching on homopitaxial growth of 4H-SiC

“…8–10 There is ample evidence from numerous studies indicating that many defects in epitaxial layers are caused by defects on the substrate surface or extensions of substrate defects. 11–13 Common methods for eliminating defects in epitaxial layers caused by substrate surface defects involve treating the substrate surface to improve the quality of the epitaxial layer. For example, common substrate surface defects such as carbon inclusions and scratches can be eliminated through surface treatment.…”

Wafer-Scale p-Type SiC Single Crystals with High Crystalline Quality

“…For decades, p-type 4H-SiC single crystals have been tried to grow via the state-of-the-art physical vapor transport (PVT) method, which has been applied to grow commercial n-type 4H-SiC single crystals up to 8-inch. 10 During the PVT process, SiC powders sublimate into Si, Si 2 C, and SiC 2 gas-phase species when heated to the growth temperature of ∼2200 °C. 10 To grow ptype SiC, Al, B, Al−B, or Al 4 C 3 powders are uniformly mixed with SiC powders.…”

“…[11][12][13]15 The biggest challenge is that the saturated vapor pressure of the p-type doping elements is considerable different from those of Si, Si 2 C, and SiC 2 at the growth temperature, resulting in polytype inclusion and doping inconsistency. 11,10,15,16 Experimentally, the growth of p-type 4H-SiC free of other polytypes, with high crystalline quality and uniform doping, still remains a challenge.…”

“…For decades, p-type 4H-SiC single crystals have been tried to grow via the state-of-the-art physical vapor transport (PVT) method, which has been applied to grow commercial n-type 4H-SiC single crystals up to 8-inch . During the PVT process, SiC powders sublimate into Si, Si 2 C, and SiC 2 gas-phase species when heated to the growth temperature of ∼2200 °C . To grow p-type SiC, Al, B, Al–B, or Al 4 C 3 powders are uniformly mixed with SiC powders. − , The biggest challenge is that the saturated vapor pressure of the p-type doping elements is considerable different from those of Si, Si 2 C, and SiC 2 at the growth temperature, resulting in polytype inclusion and doping inconsistency. ,,, Experimentally, the growth of p-type 4H-SiC free of other polytypes, with high crystalline quality and uniform doping, still remains a challenge.…”

“…However, the development of n-IGBTs is hampered mainly by the lack of wafer-scale p-type 4H-SiC single crystals with high crystalline quality. − Thus, the growth of p-type SiC is of paramount importance. For decades, p-type 4H-SiC single crystals have been tried to grow via the state-of-the-art physical vapor transport (PVT) method, which has been applied to grow commercial n-type 4H-SiC single crystals up to 8-inch . During the PVT process, SiC powders sublimate into Si, Si 2 C, and SiC 2 gas-phase species when heated to the growth temperature of ∼2200 °C .…”