In situ stress measurements during direct MOCVD growth of GaN on SiC

Zakaria Y. Al Balushi, Joan Marie Redwing

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

In situ curvature measurements were used to compare the stress evolution of GaN films grown directly on 6H-SiC via a two-step temperature growth to films grown with an AlN buffer layer. The two-step temperature growth consisted of an initial low-temperature and a main high-temperature GaN layer. In the case of GaN grown directly on 6H-SiC, the high-temperature layer initiated growth under compressive stress which transitioned to tensile stress. Films grown directly on 6H-SiC exhibited a reduction in the threading dislocation (TD) density and an improvement in the surface roughness compared to growth on the AlN buffer layer. Furthermore, transmission electron microscopy of the GaN grown directly on 6H-SiC revealed predominant (a + c)-type TD along with basal plane stacking faults and prismatic stacking faults. Channeling cracks were observed in the GaN film when the AlN buffer layer was not utilized. This was attributed to tensile stress induced from the thermal expansion coefficient mismatch.

Original languageEnglish (US)
Pages (from-to)2900-2909
Number of pages10
JournalJournal of Materials Research
Volume30
Issue number19
DOIs
StatePublished - May 14 2015

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stress measurement
Stress measurement
Metallorganic chemical vapor deposition
metalorganic chemical vapor deposition
Buffer layers
Stacking faults
Growth temperature
Tensile stress
buffers
tensile stress
crystal defects
Compressive stress
Temperature
Thermal expansion
Surface roughness
thermal expansion
Transmission electron microscopy
Cracks
surface roughness
cracks

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanical Engineering
  • Mechanics of Materials
  • Condensed Matter Physics

Cite this

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abstract = "In situ curvature measurements were used to compare the stress evolution of GaN films grown directly on 6H-SiC via a two-step temperature growth to films grown with an AlN buffer layer. The two-step temperature growth consisted of an initial low-temperature and a main high-temperature GaN layer. In the case of GaN grown directly on 6H-SiC, the high-temperature layer initiated growth under compressive stress which transitioned to tensile stress. Films grown directly on 6H-SiC exhibited a reduction in the threading dislocation (TD) density and an improvement in the surface roughness compared to growth on the AlN buffer layer. Furthermore, transmission electron microscopy of the GaN grown directly on 6H-SiC revealed predominant (a + c)-type TD along with basal plane stacking faults and prismatic stacking faults. Channeling cracks were observed in the GaN film when the AlN buffer layer was not utilized. This was attributed to tensile stress induced from the thermal expansion coefficient mismatch.",
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In situ stress measurements during direct MOCVD growth of GaN on SiC. / Al Balushi, Zakaria Y.; Redwing, Joan Marie.

In: Journal of Materials Research, Vol. 30, No. 19, 14.05.2015, p. 2900-2909.

Research output: Contribution to journalArticle

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