Micro-crack-free high power blue-violet GaN-based laser diodes grown on maskless epitaxial lateral overgrown GaN/sapphire

作者：Lee Sung Nam^*; Paek H S; Ryu H Y; Son J K; Sakong T; Jang T; Choi K K; Sung Y J; Kim Y H; Kim H K; Chae S H; Ha K H; Chae J H; Kim K S; Kwak J S; Nam O H; Park Y

来源：Journal of Crystal Growth, 2007, 298: 695-698.

DOI：10.1016/j.jcrysgro.2006.10.171

• stresses
• metalorganic chemical vapor deposition
• nitrides
• laser diodes

We observed two types of cracks with the direction of < 1 1 (2) over bar 0 > which are perpendicular to the < 1 (1) over bar 0 0 > stripe direction of seed GaN in the GaN-based laser diodes (LDs) structures grown on maskless ELO-GaN/sapphire substrates. It implies that both cracks must be generated by the anisotropic tensile stress to the direction of < I T 0 0 > originated from the lattice and thermal mismatches between AlGaN cladding layer and maskless ELO-GaN grown on the stripe seed GaN/sapphire. These cracks were easily generated by increasing the tensile strain in the LDs structures with n-AlGaN cladding layer more than about 10% Al composition in our experiment. However, in order to reduce the threshold current, it is necessary to improve the optical confinement factor (OCF) of GaN-based LDs structure by increasing the Al composition of AlGaN cladding layer. Therefore, we could achieve that the threshold current of blue-violet GaN-based LDs can reduce to 30 mA by increasing the OCF as well as suppressing the generation of crack in the LD epilayer with the n-Al0.12Ga0.88N/GaN cladding layer.

• 出版日期2007-1