Fast Lateral Epitaxial Overgrowth of Gallium Nitride by Metalorganic Chemical Vapor Deposition Using a Two-Step Process

We demonstrate a two-step process wherein the lateral epitaxial growth (LEO) of GaN from ⟨101̅0⟩ -oriented stripes is initiated at a low V/III ratio to produce smooth, vertical {112̅0} sidewalls, and where the V/III ratio is subsequently raised in order to increase the lateral growth rate. We find that the formation of the {11̅01} facets is inhibited using this two-step process, and that it is possible to maintain the {112̅0} sidewalls while achieving a large lateral growth rate. The ratio of lateral to vertical growth rate has been increased by up to factor of 2.6 using this approach relative to identical growth conditions without the initiation at low V/III ratio. The effect of lateral growth rate on the structural properties of the stripes is discussed.