Direct Epitaxial Lateral Overgrowth of GaN on Sapphire
A regrowth-free direct epitaxial lateral overgrowth method for MOCVD GaN on Sapphire is demonstrated here. The mask used is 2 μm thick SiO2 stripes with 5 μm separation and 19 μm period, formed on c-plane sapphire substrate. An uninterrupted two step growth process has been developed to obtain appropriate growth rates in vertical and horizontal directions. Coalescence has been achieved when the stripes were aligned perpendicular to the primary cut. The AFM image revealed ~1.4° surface tilt in the regrown regions. Photoluminescence study showed uniformity in the central region of the wafer and slight broadening of the spectrum, possibly due to defects in the coalescence region.
This work is funded by SERB grant number: PDF/2016/003757 and the facilities are provided by CEERI Pilani.
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