Investigation of strain and lattice parameters distribution in epitaxial laterally overgrown InGaN/GaN structures 

Aleksandra Wierzbicka 1Jaroslaw Domagala 1Marcin Sarzynski 2Daniel Luebbert 3Zbigniew R. Zytkiewicz 1

1. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland
2. Polish Academy of Sciences, Institute of High Pressure Physics (UNIPRESS), Sokolowska 29/37, Warszawa 01-142, Poland
3. Humboldt-Universität, Newtonstr. 15, Berlin 12489, Germany

Abstract

GaN and its ternary alloys with In and Al (InGaN, AlGaN) are wide and direct band gap semiconductor materials used for fabrication of optoelectronic devices such as light emitting diodes and laser diodes. However, due to limited availability of suitable bulk substrates many types of device structures are still grown on foreign substrates. As a result, high dislocation density in planar epitaxial layers (108-109/cm2) strongly limits the efficiency of radiative recombination processes. One way to overcome this issue is when the planar architecture of the layer is gradually replaced by more sophisticated 3 dimensional structures in order to efficiently decrease the dislocation density in lattice mismatched epitaxial layers. In particular, remarkable results are achieved by application of the Epitaxial Lateral Overgrowth (ELO) approach. There are many reports showing that ELO is a powerful technique for reducing dislocation density by 3–4 orders of magnitude.

Fig. 1. Schematic cross-section (a) and plane view (b) of InGaN/GaN ELO layer on sapphire substrate covered by GaN buffer and by SiO2 mask. Stripes are parallel to (11-20) direction. Panel (c) presents SEM image of the single ELO stripe. Part (d) shows experimental results of spatial distribution of  local diffraction intensity in the sample measured with the diffraction plane parallel to the seeding lines. Pixel size is 1.4 µm.

 

The aim of this work was to investigate with synchrotron, using spatially resolved Rocking Curve Imaging (RCI) technique, distribution of strain and lattice parameters in specially designed ELO structures [1]. The samples studied are composed as follows: first the epitaxial GaN layer on sapphire substrate was covered by a thin SiO2 mask. Next the 3 µm wide seeding windows spaced by 15 µm were opened in the mask. The growth of the GaN ELO layers by metal-organic chemical-vapor deposition (MOCVD) started in mask free seeding areas of the GaN/sapphire template. Finally the five InGaN quantum wells with GaN barriers were grown on GaN stripes (Fig. 1a-c). Figures 1(a) and (b) show schematic cross-section of two ELO stripes and plane view of the structure, respectively. The SEM image (Fig. 1c) shows a  characteristic shape of the single ELO stripe.

 Such sophisticated architecture of the sample is ideal to demonstrate the potential of RCI technique. As it was reported earlier [2] the RCI technique combines the features of X-ray imaging (very high spatial resolution) and X-ray diffractometry (very high angular resolution). In our experiment the monochromatic synchrotron X-ray beam illuminates the sample which is rotated in small steps around an axis perpendicular to the diffraction plane near its Bragg angle. The diffraction images are recorded for each angular position of the sample by using a CCD camera (2048×2048 pixels, 1.4μm pixel size). The signal is analyzed with specialized software [1]. Experiments reported here were performed at the beamline ID19 in ESRF, Grenoble, France. Figure 1(d) presents the spatial distribution of local diffraction intensities in the sample. Signals originating from the GaN buffer and the ELO InGaN/GaN stripes are clearly distinguished. Even local mosaicity on the stripes is detected, which is due to high spatial resolution offered by RCI technique. The results of RCI analysis are compared with those obtained by laboratory technique of spatially resolved X-ray diffraction (SRXRD) [3]. Unfortunately, a small distance between seeding windows resulted in an overlap of signals originating from individual stripes, so it was very hard to investigate spatial distribution of sample parameters. Therefore, we found RCI technique irreplaceable to see differences between InGaN/GaN stripes and the rest of the sample.

  

Acknowledgments: This work was partially supported by the European Union within European Regional Development Fund, through grant Innovative Economy (POIG.01.01.02-00-008/08 NanoBiom) and by special project ESRF/MA/623/2009 from the Polish Ministry of Science and High Education.

References

[1] D. Lübbert, T. Baumbach, P. Mikulik, P. Pernot, L. Helfen, R. Kohler, T. M. Katona,   S. Keller, S. P. DenBaars, J. Phys. D: Appl. Phys. 38 (2005) A50.

[2] A. Wierzbicka, D. Lübbert, J.Z. Domagala, Z.R. Zytkiewicz, Acta Phys. Pol. A, 116  (2009) 976.

[3] J.Z. Domagala, A. Czyzak, Z.R. Zytkiewicz, Appl. Phys. Lett. 90 (2007) 241904.

 

Related papers
  1. Growth and properties of inclined GaN nanowires on Si(001) substrates by PAMBE
  2. Optimization of nitrogen plasma source parameters for growth of GaN by MBE
  3. Defect distribution along needle-shaped PrVO4 single crystals grown by the slow-cooling method
  4. Mechanism of in-plane orientation of GaN self-induced nanowires grown on Si(111) substrates 
  5. Bulk GaAs growth by Contactless Liquid Phase Electroepitaxy
  6. GaN substrates with variable surface miscut for laser diode applications
  7. Impact of substrate microstructure on self-induced nucleation and properties of GaN nanowires grown by plasma-assisted MBE
  8. Modelling of X-Ray diffraction curves for GaN nanowires on Si(111)
  9. Measurements of strain in AlGaN/GaN HEMT structures grown by plasma assisted molecular beam epitaxy
  10. Photoreflectance study of Ga(Bi,As) and (Ga,Mn)As epitaxial layers grown under tensile and compressive strain
  11. MBE growth, structural, magnetic, and electric properties of (In,Ga)As-(Ga,Mn)As core-shell nanowires
  12. MBE growth of GaN nanowires on Si(111) substrates for gas sensor applications 
  13. Quaternary (Ga,Mn)BiAs ferromagnetic semiconductor -MBE growth, structural and magnetic properties
  14. Electronic and optical properties – As and As+Sb doped ZnO grown by PA-MBE
  15. Epitaxial growth and characterization of zinc oxide nanorods obtained by the hydro-thermal method
  16. Grown ZnMgO/ZnO/ZnMgO heterostructures on p-type Si(111) by MBE method
  17. Dual-acceptor doped p-ZnO:(As+Sb)/n-GaN heterojunctions grown by PA-MBE as a highly selective UV detector
  18. Influence of substrate on crystallographic quality of AlGaN/GaN HEMT structures grown by MBE
  19. X-ray measurements of type II InAs/GaSb superlattice in a wide angular range using the P08 beamline at PETRAIII
  20. Monocrystalline character of ZnMgTe shell in the core-shell ZnTe/ZnMgTe nanowires
  21. Innowacyjne technologie wielofunkcyjnych materiałów i struktur dla nanoelektroniki, fotoniki, spintroniki i technik sensorowych (InTechFun).
  22. Surface morphology of InGaN layers
  23. Zinc oxide grown by Atomic Layer Deposition - a material for novel 3D electronics
  24. Dimethylzinc and diethylzinc as precursors for monocrystalline zinc oxide grown by Atomic Layer Deposition
  25. Structure of Si:Mn annealed under enhanced stress conditions
  26. Effect of high pressure annealing on defect structure of GaMnAs
  27. Influence of high temperature annealing on the local atomic structure around Mn atoms and magnetic properties of (Ga,Mn)As layers
  28. Catalytic growth by molecular beam epitaxy and properties of ZnTe-based semiconductor nanowires
  29. X-ray Diffraction as a Tool of InGaN layer Characterization.
  30. Structural inhomogenities in GdCa4O(BO3)3 single crystals
  31. Liquid phase growth and characterization of laterally overgrown GaSb epitaxial layers
  32. Distribution of strain in laterally overgrown GaAs layers determined by x-ray diffraction
  33. Determination of stress in composite engineered substrates for GaN-based RF power devices
  34. Effect of stress on structural transformations in GaMnAs
  35. X-ray imaging for applied and industrial research - applications in microelectronics and in micro system technology
  36. Growth and characterization of thin films of ZnO by Atomic Layer Epitaxy
  37. Bowing of epitaxial structures grown on bulk GaN substrates
  38. Structure modifications in materials irradiated by ultra-short pulses of VUV free electron laser
  39. Defects in GaMnAs - influence of annealing and growth conditions
  40. High-pressure phase transition and compressibility of zinc-blende HgZnSe mixed crystals
  41. Novel substrates for heteroepitaxy by lateral overgrowth technology
  42. Lattice parameters changes of GaMnAs layers induced by annealing

Presentation: Poster at IX Krajowe Sympozjum Użytkowników Promieniowania Synchrotronowego, by Aleksandra Wierzbicka
See On-line Journal of IX Krajowe Sympozjum Użytkowników Promieniowania Synchrotronowego

Submitted: 2011-06-14 17:03
Revised:   2011-06-28 10:58