Scanning capacitance microscopy imaging of threading dislocations in GaN films grown on (0001) sapphire by metalorganic chemical vapor deposition

A combination of atomic force microscopy and scanning capacitance microscopy was used to investigate the relationship between the surface morphology and the near-surface electrical properties of GaN films grown on c-axis sapphire substrates by metalorganic chemical vapor deposition. Local regions surrounding the surface termination of threading dislocations displayed a reduced change in capacitance with applied voltage relative to regions that contained no dislocations. Capacitance–voltage characteristics obtained from these regions indicated the presence of negative charge in the vicinity of dislocations.

[1]  M. Skowronski,et al.  Observation of nanopipes in α-GaN crystals , 1995 .

[2]  S. Denbaars,et al.  Homoepitaxial growth of GaN under Ga-stable and N-stable conditions by plasma-assisted molecular beam epitaxy , 1997 .

[3]  Fernando Ponce,et al.  High dislocation densities in high efficiency GaN‐based light‐emitting diodes , 1995 .

[4]  Sven Öberg,et al.  Theory of Threading Edge and Screw Dislocations in GaN , 1997 .

[5]  S. Nakamura,et al.  InGaN-Based Multi-Quantum-Well-Structure Laser Diodes , 1996 .

[6]  M. Asif Khan,et al.  Violet‐blue GaN homojunction light emitting diodes with rapid thermal annealed p‐type layers , 1995 .

[7]  M. Shur,et al.  GaN/AIGaN Heterostructure Devices: Photodetectors and Field-Effect Transistors , 1997 .

[8]  James R. Matey,et al.  Scanning capacitance microscope , 1985 .

[9]  X. H. Wu,et al.  Morphological and Structural Transitions in GaN Films Grown on Sapphire by Metal-Organic Chemical Vapor Deposition , 1996 .

[10]  James S. Speck,et al.  Defect structure of metal‐organic chemical vapor deposition‐grown epitaxial (0001) GaN/Al2O3 , 1996 .

[11]  U. K. Mishra,et al.  Metalorganic chemical vapor deposition growth of high optical quality and high mobility GaN , 1995 .

[12]  H. Amano,et al.  Growth mechanism of GaN grown on sapphire with A1N buffer layer by MOVPE , 1991 .

[13]  Takashi Mukai,et al.  High‐brightness InGaN/AlGaN double‐heterostructure blue‐green‐light‐emitting diodes , 1994 .

[14]  Hemantha K. Wickramasinghe,et al.  Lateral dopant profiling with 200 nm resolution by scanning capacitance microscopy , 1989 .

[15]  David P. Bour,et al.  Spatial distribution of the luminescence in GaN thin films , 1996 .

[16]  M. Skowronski,et al.  Open‐core screw dislocations in GaN epilayers observed by scanning force microscopy and high‐resolution transmission electron microscopy , 1995 .

[17]  James S. Speck,et al.  Role of threading dislocation structure on the x‐ray diffraction peak widths in epitaxial GaN films , 1996 .

[18]  Henryk Temkin,et al.  Low noise p-π-n GaN ultraviolet photodetectors , 1997 .

[19]  James S. Speck,et al.  Structural evolution in epitaxial metalorganic chemical vapor deposition grown GaN films on sapphire , 1995 .

[20]  P. Vennégués,et al.  Study of open-core dislocations in GaN films on (0001) sapphire , 1997 .

[21]  E. C. Carr,et al.  CORRELATION OF CATHODOLUMINESCENCE INHOMOGENEITY WITH MICROSTRUCTURAL DEFECTS IN EPITAXIAL GAN GROWN BY METALORGANIC CHEMICAL-VAPOR DEPOSITION , 1997 .