Improvement of epitaxial GaN films grown on patterned sapphire substrate by growth mode control

Dae Sik Kim, Chang Min Lee, Woo Seop Jeong, Seung Hee Cho, Junggeun Jhin, Dong Jin Byun

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Epitaxial GaN films were grown via metal-organic chemical vapor deposition (MO-CVD) on a cone-shaped patterned sapphire substrate (PSS). A 25 nm thick AlN was deposited by ex-situ sputtering as a buffer layer. The GaN films were grown under various conditions by controlling the substrate temperature (1020-1100°C) and working pressure (85-300 Torr). GaN films grown on PSS via the conventional two-step growth mode consisting of vertical (three-dimensional; 3D) growth and horizontal (two-dimensional; 2D) growth contained poly-grains on top of the cone-shaped pattern. The growth of multi-directional poly-grains on top of the cone-shaped pattern generated numerous defects even though the GaN films were grown by the epitaxial lateral overgrowth (ELO) process. In this paper, we introduce an effective method to control the growth mode of GaN on PSS during the ELO process. The GaN films grown on PSS via the optimized growth mode control showed improvement of crystal quality and surface roughness. The surface morphology and roughness of the GaN films were investigated by field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) in non-contact mode, respectively. The crystal quality of the GaN films was evaluated by ω-2θ high-resolution X-ray diffraction (HR-XRD) and the cathodoluminescence (CL) was measured in the 300-800 nm wavelength range to confirm the distribution of threading dislocations.

Original languageEnglish
Pages (from-to)11575-11579
Number of pages5
JournalJournal of Nanoscience and Nanotechnology
Volume16
Issue number11
DOIs
Publication statusPublished - 2016

Keywords

  • Epitaxial lateral overgrowth
  • Gallium nitride
  • Metal-organic chemical vapor deposition
  • Patterned sapphire substrate
  • Thin film

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Improvement of epitaxial GaN films grown on patterned sapphire substrate by growth mode control'. Together they form a unique fingerprint.

  • Cite this