Effect of sapphire substrate orientation on the surface morphology and structural quality of thick GaN layers grown by hydride vapor phase epitaxy.

Donskov, A.; Dyakonov, L.; Kozlova, Yu.; Malakhov, S.; Mezhennyi, M.; Pavlov, V.; Yugova, T.

The effect of substrate orientation on the surface orientation of thick GaN layers grown by hydride vapor phase epitaxy (HVPE) has been established. Layers oriented along the (0001), (11 $$ \bar 2 $$0), and (10 $$ \bar 1 $$3) planes have been obtained on, respectively, c- and a-, r-, and m-oriented substrates. Depending on the orientation of the GaN layer surface, surface defects (terraces and growth pits) are faceted by different planes whose intersections with the growth surface are perpendicular to the direction of growth pit faces. It is found that the sapphire substrate surface orientation has an effect on the layer structural quality (which increases with an increase in the layer thickness, regardless of the layer orientation). The directions of crack propagation in the GaN layer also depend on the surface orientation of the layer and are mainly determined by the intersections of the {1 $$ \bar 1 $$00} planes of the layer with the surface.

SAPPHIRES; SUBSTRATES (Materials science); MOLECULAR structure; GALLIUM nitride; CRYSTAL growth; HYDRIDES; EPITAXY; SURFACE defects; THICKNESS measurement

Crystallography Reports, 2011, Vol 56, Issue 2, p274

1063-7745

Academic Journal

10.1134/S1063774511020052