Selective Area Growth of GaN Using Tungsten Mask by Metalorganic Vapor Phase Epitaxy

We studied selective area growth (SAG) of GaN using a tungsten (W) mask with an atmospheric metalorganic vapor phase epitaxy (MOVPE) system. No GaN polycrystals were observed on the W mask regions, and the selectivity of GaN growth on window regions proved to be excellent. The GaN stripes developed into different shapes depending on the direction of stripe mask patterns. If the stripe was along <1120>, a triangular shape with {1101} facets was formed. If the stripe was along <1100>, a trapezoidal shape with a smooth (0001) surface on top and rough surfaces on both sides was obtained. The lateral overgrowth of GaN on the W mask occurred in both cases. The growth mechanisms and the facet formation were similar to those found in SAG using a SiO₂ mask.