Selective Area Growth (SAG) and Epitaxial Lateral Overgrowth (ELO) of GaN Using Tungsten Mask

Abstract

Selective area growth (SAG) and epitaxial lateral overgrowth (ELO) of GaN using tungsten (W) mask by metalorganic vapor phase epitaxy (MOVPE) and hydride vapor phase epitaxy (HVPE) have been studied. The selectivity of the GaN growth on the W mask as well as the SiO₂ mask is excellent for both MOVPE and HVPE. The ELO-GaN layers are successfully obtained by HVPE on the stripe patterns along the <11¯00> crystal axis with the W mask as well as the SiO₂ mask. There are no voids between the SiO₂ mask and the overgrown GaN layer, while there are triangular voids between the W mask and the overgrown layer. The surface of the ELO-GaN layer is quite uniform for both mask materials. In the case of MOVPE, the structures of ELO layers on the W mask are the same as those on the SiO₂ mask for the <112¯0> and <11¯00> stripe patterns. No voids are observed between the W or SiO₂ mask and the overgrown GaN layer by using MOVPE.