Epitaxial lateral overgrowth of GaN on selected-area Si(1 1 1) substrate with nitrided Si mask

Abstract

Epitaxial lateral overgrowth (ELO) of GaN by metalorganic vapor phase epitaxy was carried out on Si substrates using new ELO-mask patterns. The groove or SiO 2 mask pattern employed was a stripe in combination with a larger period grid (100 μm×100 μm): the former is for the ELO of the GaN to reduce the threading dislocation (TD) density and the latter is for limiting the area of growth and to suppress the formation of cracks in the grown GaN. Crack-free GaN layers with a reduced TD density were successfully obtained for both types of Si substrate, i.e., the grooved Si substrate and the SiO 2-masked Si substrate. The properties of GaN layers grown on these Si substrates are compared.