Silicon Carbide Purification by Formation of Thin Porous Layer Followed by Thermal Annealing for Silicon Passivation

摘要

In this paper, we discussed a rapid and low cost technique of commercial silicon carbide (SiC) powder purification. Purified powders were used as target to deposit SiC thin layers on silicon substrates by pulsed laser deposition technique (PLD). The purification process is based on the porosification of SiC powder followed by a rapid thermal annealing under oxygen atmosphere. The impact of the etching duration and annealing temperature on the purification efficiency was presented. The purity of SiC powder was improved from 99.9771% (3N) to 99.9990% (5N) with an impurity removal efficiency of 96.56% for an etching duration of 10 min and an annealing temperature of 950 °C. A significant enhancement of the minority carrier lifetime in silicon was obtained.