Faceted growth of ({\bf {\overline 1}103})-oriented GaN domains on an SiO₂-patterned m-plane sapphire substrate using polarity inversion

Abstract

Heteroepitaxial growth of ({\overline 1}103)-oriented GaN domains on m-plane sapphire is energetically unfavourable in comparison with that of (1{\overline 1}0{\overline 3})-oriented GaN domains, but the faceted domains with ({\overline 1}103)-oriented GaN reveal a more m-facet-dominant configuration than (1{\overline 1}0{\overline 3})-oriented GaN in such a way that the quantum-confined Stark effect can be more effectively suppressed. It is reported here, for the first time, that semipolar ({\overline 1}103)-oriented and faceted GaN domains can be grown on an SiO2-patterned m-plane sapphire substrate by employing polarity inversion of initially nucleated (1{\overline 1}0{\overline 3})-oriented GaN domains. This polarity inversion of semipolar GaN was found to occur when the domains were grown with a 20–37.5 times higher V/III ratio and 70 K lower growth temperature than corresponding parameters for polarity-not-inverted domains. This work opens up a new possibility of effective suppression of the quantum-confined Stark effect by polarity-controlled semipolar GaN in an inexpensive manner in comparison with homoepitaxial growth of ({\overline 1}103)-oriented GaN on a GaN substrate.

Inversion domain boundary structure of laterally overgrown c-GaN domains including the inversion from Ga to N polarity at a mask pattern boundary

“…Thus, wet etching in a KOH solution was carried out for polarity identification in this work. Computational simulations were carried out on 800 Â 800 grids to calculate the plan-view shape of a c-GaN domain in PILO by numerically integrating a level set equation; a similar approach has been described elsewhere (Osher & Fedkiw, 2003;Lee et al, 2014Lee et al, , 2018Yoon et al, 2017).…”

Defect characterization of {101¯3} GaN by electron microscopy

“…This, in turn, led to poor surface morphologies dominated by twin boundaries and high defect densities. [11][12][13] However, recently untwinned (10 13) GaN layers have been achieved by patterned MOVPE 14 and HVPE growth, 15,16 as well as by directional sputtering on both (001) Si 17,18 and m-plane sapphire. 9,19 Using directional sputtering, (10 13) oriented Al(Ga)N has been grown on m-plane sapphire as well.…”