Influence of growth temperature on surface morphologies of GaN crystals grown on dot-patterned substrate by hydride vapor phase epitaxy

Hai Ping Liu, In Gann Chen, Jenq Dar Tsay, Wen Yueh Liu, Yih Der Guo, Jung Tsung Hsu

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

This paper studies the influence of growth temperatures in the range 825 to 1050°C on the surface morphologies of GaN crystals grown on a SiO 2 dot-patterned substrate using Epitaxy Lateral Overgrowth (ELO) and Hydride Vapor Phase Epitaxy (HVPE) techniques. A lower growth temperature of 850°C prompts the formation of GaN hexagonal pyramidal crystals with a higher fraction of Fcet areas than those grown at high temperatures (>1000°C). In a subsequent coalescent (or lateral growth) process, a high temperature of 1050°C is applied to the original GaN hexagonal pyramidal crystals, and the morphologies of the GaN layers are inspected. It is established that the original morphology of the hexagonal pyramids changes to an irregularly-shaped surface comprising overline 2 s, and that the nature of the surface morphology is influenced by the growth time and the application (or not) of Ga precursor support. Hence, the results show that the coalescence and planarization of the GaN layer can be controlled through an appropriate specification of the process parameters. At low temperatures in the region of 850°C, high index facets are observed on the tops of a small percentage of the hexagonal GaN columnar crystals. It is proposed that this phenomenon is caused by a reduction in the surface diffusion length of the precursors, e.g. NH3 and GaCl, at lower temperature, which in turn, reduces the probability of desorption and increases the lifetime.

Original languageEnglish
Pages (from-to)839-846
Number of pages8
JournalJournal of Electroceramics
Volume13
Issue number1-3
DOIs
Publication statusPublished - 2004 Jul 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Mechanics of Materials
  • Electrical and Electronic Engineering
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Influence of growth temperature on surface morphologies of GaN crystals grown on dot-patterned substrate by hydride vapor phase epitaxy'. Together they form a unique fingerprint.

Cite this