Porous graphite plate design in SiC PVT growth: optimized powder source evolution for enhanced crystal yield and quality

Abstract

The third-generation semiconductor, silicon carbide (SiC), has become increasingly crucial in emerging markets for radio-frequency and power electronic devices due to its superior physical properties. However, the insufficient growth thickness and low powder source utilization rate still limit the development of physical vapor transport (PVT) growth. In this work, a systematic investigation on the evolution progress and consumption features of the SiC powder source in PVT growth was conducted by theoretical simulations and experimental measurements. We found that the non-uniform source consumption and recrystallization negatively impacted the evolution of thermal and flow fields, resulting in a final low utilization rate of the powder source. To enhance the usage of the powder source and the quality of as-grown crystals, we designed a porous graphite plate in the PVT chamber to modulate both mass transfer processes and the thermal field. Compared to a conventional structure, the designed porous graphite plate could optimize the utilization rate (29% enhanced) and the spatial uniformity of source consumption, thereby increasing the crystal growth rates by 33%. Meanwhile, this designed plate could reduce the thermal stress gradients and thus reduce the defect density (52%) within the SiC crystals.