Crack-free GaN grown by using maskless epitaxial lateral overgrowth on Si substrate with thin SiC intermediate layer

摘要

With 100-nm-thick 3C-SiC intermediate layer, GaN layer of relative high quality was obtained on Si substrate by using a maskless epitaxial lateral overgrowth (ELO). The three-dimensional growth of maskless ELO process was investigated with wafer reflectance collected during growth. Low temperature cathodoluminescence observation confirmed the improve- ment of the GaN quality by ELO. An AlN interlayer was used to prevent crack of the GaN epilayer. As a result, the as-grown GaN layer shows a crack-free surface with long atomic steps. The threading dislocation density is lower than 1 × 10~9 cm~(-2) in GaN layer underneath AlN interlayer.