Influence of ambient gas on the epitaxial lateral overgrowth of GaN by metalorganic vapor phase epitaxy

The influence of ambient gas species on epitaxial lateral overgrowth using selective area growth is studied by metalorganic vapor phase epitaxy. When the stripe direction is along the [1 (1) over bar 00] crystal axis, trapezo idal cross-sectional shape with smooth (0001) surface on the top is obtaine d in Hz ambient gas. On the other hand, in N-2 ambient gas; regardless of t he coalescence of lateral overgrown regions, a smooth surface is not obtain ed, it is undulated according to the stripe pattern, and there are voids be tween coalesced regions. In a sample grown in N-2, analyses of the selected area diffraction and X-ray rocking curves show that the c-axis lilts about 13 degrees toward the [11 (2) over bar 0] direction on the coalesced regio n.