Polyimide-derived graphite barrier layer adhered to seed crystals to improve the quality of grown silicon carbide

A facial method was developed to in situ fabricate a graphite layer on a SiC seed crystal to reduce the formation of defects during the growth of SiC ingots. The formulated PI matrix combined with an appropriate coupling agent could strongly adhere to SiC and be transformed into protective layers for SiC seed crystals during SiC growth. The thermally conductive graphite layers on SiC effectively reduce the backside diffusion of Si, inhibit the loss of Si from seed crystals during high-temperature growing process, and consequently lead to fewer defects formed in the SiC ingot. The graphitization degree, chemical state, roughness and morphology of films were investigated in this work.