Dislocation reduction in GaN film using Ga-lean GaN buffer layer and migration enhanced epitaxy

作者：Wong Yuen Yee; Chang Edward Yi^*; Wu Yue Han; Hudait Mantu K; Yang Tsung Hsi; Chang Jet Rung; Ku Jui Tai; Chou Wu Ching; Chen Chiang Yao; Maa Jer Shen; Lin Yueh Chin

来源：Thin Solid Films, 2011, 519(19): 6208-6213.

DOI：10.1016/j.tsf.2011.03.054

• Molecular beam epitaxy
• Gallium nitride
• Dislocations
• Ga-lean gallium nitride
• Migration enhanced epitaxy
• Atomic force microscopy
• High-resolution X-ray diffraction
• Transmission electron microscopy

A GaN buffer layer grown under Ga-lean conditions by plasma-assisted molecular beam epitaxy (PAMBE) was used to reduce the dislocation density in a GaN film grown on a sapphire substrate. The Ga-lean buffer, with inclined trench walls on its surface, provided an effective way to bend the propagation direction of dislocations, and it reduced the dislocation density through recombination and annihilation processes. As a result, the edge dislocation density in the GaN film was reduced by approximately two orders of magnitude to 2 x 10(8) cm(-2). The rough surface of the Ga-lean buffer was recovered using migration enhanced epitaxy (MEE), a process of alternating deposition cycle of Ga atoms and N(2) radicals, during the PAMBE growth. By combining these two methods, a GaN film with high-crystalline-quality and atomically-flat surface can be achieved by PAMBE on a lattice mismatch substrate.

• 出版日期2011-7-29
• 单位Virginia Tech; 美国弗吉尼亚理工大学(Virginia Tech)