Anisotropy of tensile stresses and cracking in nonbasal plane Al{sub x}Ga{sub 1-x}N/GaN heterostructures

Journal Article · Mon Jan 25 04:00:00 EST 2010 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.3276561· OSTI ID:21347252

Young, Erin C; Gallinat, Chad S; Hirai, Asako; Speck, James S ^[1]; Romanov, Alexey E ^[1]; Beltz, Glenn E ^[2]

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1. Department of Materials, University of California, Santa Barbara, California 93106 (United States)
2. Department of Mechanical Engineering, University of California, Santa Barbara, California 93106 (United States)

Al{sub x}Ga{sub 1-x}N films grown on nonpolar m (1100) and (1122) semipolar orientations of freestanding GaN substrates were investigated over a range of stress states (x<=0.17). Cracking on the (0001) plane was observed beyond a critical thickness in the (1100) oriented films, while no cracking was observed for (1122) films. Theoretical analysis of tensile stresses in Al{sub x}Ga{sub 1-x}N for the relevant planes revealed that anisotropy of in-plane biaxial stress for the nonpolar (1100) planes results in the highest normal stresses on the c-planes, consistent with experimental observations. Shear stresses are significant in the semipolar case, suggesting that misfit dislocation formation provides an alternative mechanism for stress relief.

• OSTI ID: 21347252
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 4 Vol. 96; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM COMPOUNDS
ALUMINIUM NITRIDES
ANISOTROPY
ATOMIC FORCE MICROSCOPY
CHEMICAL REACTIONS
CRACKING
CRACKS
CRYSTAL DEFECTS
CRYSTAL GROWTH
CRYSTAL GROWTH METHODS
CRYSTAL STRUCTURE
DECOMPOSITION
DIMENSIONS
DISLOCATIONS
EPITAXY
FILMS
GALLIUM COMPOUNDS
GALLIUM NITRIDES
HETEROJUNCTIONS
LINE DEFECTS
MATERIALS
MECHANICAL PROPERTIES
MICROSCOPY
MOLECULAR BEAM EPITAXY
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
PYROLYSIS
SEMICONDUCTOR JUNCTIONS
SEMICONDUCTOR MATERIALS
SHEAR PROPERTIES
STRESSES
SUBSTRATES
TENSILE PROPERTIES
THERMOCHEMICAL PROCESSES
THICKNESS
THIN FILMS