Selective Growth of GaN and Al0.2Ga0.8N on GaN/AlN/6H-SiC (0001) Multilayer Substrates Via Organometallic Vapor-Phase Epitaxy

Abstract
The selective growth of GaN and Al0.2Ga0.8N has been conducted on stripe and circular patterned GaN/A1N/6H-SiC(0001) multilayer substrates. Growth morphologies on stripe patterns changed with the widths of stripes and the flow rate of TEG. No ridge growth was observed along the edges of the stripe patterns, and the (0001) top facets were very smooth. Uniform hexagonal pyramid arrays of undoped GaN and Si-doped GaN were successfully grown on 5μm circular patterns. Field emission measurement of a Si-doped GaN hexagonal pyramid array exhibited a turn-on field of 25V/μm for an emission current of 10.8nA at an anode-to-sample distance of 27μm.