Pretreatment by selective ion-implantation for epitaxial lateral overgrowth of GaN on patterned sapphire substrate

• Published in: Thin solid films Vol. 641; pp. 2 - 7
• Main Authors: Kim, Dae-sik, Jeong, Woo Seop, Ko, Hyungduk, Lee, Jae-Sang, Byun, Dongjin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2017
• Subjects: Epitaxial lateral overgrowth; Gallium nitride; Ion-implantation; Metal organic chemical vapor deposition; Patterned sapphire substrate; Metal organic chemical vapor deposition; Patterned sapphire substrate; Epitaxial lateral overgrowth; Gallium nitride; Ion-implantation
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2017.06.042

Epitaxial lateral overgrowth (ELO) process of gallium nitride (GaN) films on cone-shaped patterned sapphire substrate (PSS), which was pretreated by ion-implantation was performed by using a metal organic chemical vapor deposition. A 250-nm-thick silicon dioxide (SiO2) mask was covered on the planar surface of the PSS to protect them from ion-implantation damages, whereas the cone-shaped patterns of the PSS were exposed to collide with the N+ ions. The ion-implantation pretreatment was selectively carried out on the cone-shaped pattern of PSS at 67.5keV with a high dose of 5×1017cm−2. As a result of ion-implantation pretreatment, nucleation growth of GaN poly-grains was inhibited on the cone-shaped patterns with various crystal planes, such as c-like plane, R-like plane, and n-like plane. Surface roughness and crystal quality of GaN films grown on ion-implanted PSS were improved owing to the inhibition of nucleation growth on the patterns. The ion-implantation pretreatment is a very promising technique in the ELO process of GaN on an uneven substrate such as a cone-shaped PSS that includes various crystal planes. •N+ ions were selectively implanted into cone-shaped patterned sapphire substrates (PSS).•GaN nucleation was prevented by ion-implantation on cone-shape patterns.•GaN films were grown without poly-grains on PSS.•The PSS pretreatment improved the surface roughness and crystal quality of the GaN films.