Growth of GaN and Al_0.2Ga_0.8N on Patterened Substrates via Organometallic Vapor Phase Epitaxy

Abstract

The selective growth of GaN and Al 0.2 Ga 0.8 N has been achieved on stripe and circular patterned GaN/AlN/6H-SiC(0001) multilayer substrates. Growth morphologies on the stripe patterns were a function of the widths of the stripes and the flow rate of triethylgallium. No ridge growth was observed along the top edges of the truncated stripe patterns. Smooth (0001) top facets formed on stripes ≥5 µ m wide. Uniform hexagonal pyramid arrays of undoped GaN and Si-doped GaN were successfully grown on 5 µ m circular patterns. Field emission measurements of a Si-doped GaN hexagonal pyramid array exhibited a turn-on field of 25 V/µ m for an emission current of 10.8 nA at an anode-to-sample distance of 27 µ m.