Anisotropic coalescence behaviors of GaN islands grown by metal-organic chemical vapor deposition

Abstract

In Epitaxial Lateral Overgrowth (ELO) technology, GaN is grown inside the stripe window of a SiO2 mask and then grow laterally over the mask to eventually merge and form a uniform thin film. GaN islands have hexagonal foot prints and can merge along the direction where the two parallel sides of the hexagonal islands are aligned parallel or along the direction where their tips are pointed towards one another. Growth along the 〈11 2 0〉 is found to be faster than along the 〈1 1 00〉 by a ratio of 1:0.85. After merging, the island shows different shapes which affect the strain within the island and the bending of dislocations. During the growth of the stripes to form triangular ridges, the facets are found to be different on stripes aligned along 〈11 2 0〉 compare to the facets which are formed on stripes aligned along 〈1 1 00〉. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.