Enlargement of SiC Crystals: Defect Formation at the Interfaces

Formation of thermal decomposition cavities in physical vapor transport of silicon carbide

“…[5][6][7] As an illustration of this difference, Figure 1 shows an optical micrograph of a cross-section of a PVT crystal containing both types of voids.…”

“…Several authors have noted that thermal decomposition cavities originate at the interface between the SiC seed and the graphite seed holder. 4,7,8 Vodakov et al 7 proposed that thermal decomposition cavities form by a recrystallization process in which SiC is transported across small gaps or liquid droplets at the holder/SiC interface. Similarly, Anikin et al 8 suggested that they form by localized sublimation from the back of the relatively hot seed to a relatively cool graphite seed holder.…”

“…It has also been shown that tubular voids in SiC wafers can be overgrown by thick epitaxial layers 8 and that they usually end abruptly in the crystal at plate-like inclusions or voids. 7 Micropipes, on the other hand, propagate during successive growth steps from the seed to the overgrown layer. 9 Considering the fact that micropipes are associated with dislocations, this propagation is almost inevitable.…”

“…11,12 Most authors agree that voids in the carbonized sucrose attachment layer at the seed crystal/crucible lid interface create thermal decomposition cavities. 5,7,8,13 This paper has two objectives. The first is to describe the mechanism by which voids in the attachment layer create thermal decomposition cavities.…”

Synthesis and Growth of 6H-SiC and 3C-SiC in an Al–Si–C System at 820 °C: Effect of the Reaction Path on the SiC Polytype

“…Growth parameters like temperature, pressure, and supersaturation have a strong influence on the SiC polytype during the physical vapor transport (PVT) process. By adjusting these three factors, the growth characteristics of 4H and 6H SiC can be changed, and the transition between 4H-SiC and 6H-SiC can also be observed. − Other factors such as impurities, surface types, offsets of the substrate, and atmospheric conditions are also important for the synthesis of SiC with a specific polytype in the PVT method. − For SiC obtained by the chemical vapor deposition (CVD) method, 3C-SiC is the typical polytype . However, by proper selection of precursor and controlled synthesis parameters, 2H-SiC, 4H-SiC, and 6H-SiC can also be obtained. − During the CVD process, the SiC polytype has a close relationship with the silicon-to-carbon (Si/C) ratio.…”