Cracking of GaN films

Etzkorn, E. V.; Clarke, D. R.
January 2001
Journal of Applied Physics;1/15/2001, Vol. 89 Issue 2, p1025
Academic Journal
Cracking of thick GaN films grown on sapphire is reexamined on the basis of a combination of microstructural observations of cracking and established mechanics of fracture of films. It is argued that cracking is motivated by tensile growth stresses once a critical thickness is reached. Subsequent growth on the cracked films occurs, perpetuating the cracked structure until the crack surfaces approach one another and touch. Continued film growth buries the crack. Once the crack faces touch, there are conditions under which it is energetically favorable for the cracks to close and heal. Crack healing can be kinetically limited. Whether the crack healing is complete within the growth time depends on several factors including, it is suggested, whether impurities have adsorbed to the surface during growth. Conditions under which cracks that have extended into the sapphire substrate during film growth can act as critical flaws for fracture of the substrate on cooling are also presented. © 2001 American Institute of Physics.


Related Articles

  • Dislocation reduction in GaN grown by hydride vapor phase epitaxy via growth interruption modulation. Zhang, Wei; Roesel, Stephan; Alves, Helder R.; Meister, Dirk; Kriegseis, Wilhelm; Hofmann, Detlev M.; Meyer, Bruno K.; Riemann, Till; Veit, Peter; Blaesing, Juergen; Krost, Alois; Christen, Juergen // Applied Physics Letters;2/5/2001, Vol. 78 Issue 6, p772 

    Thick GaN layers have been deposited on c-Al[sub 2]O[sub 3] (0001) substrates using hydride vapor phase epitaxy by modulating the growth process via switching on/off GaN growth. Cathodoluminescence and transmission electron microscopy images of the cross-sectional structure show that there are...

  • Defect structure in selectively grown GaN films with low threading dislocation density. Sakai, Akira; Sunakawa, Haruo // Applied Physics Letters;10/20/1997, Vol. 71 Issue 16, p2259 

    Characterizes defect structures in gallium nitride (GaN) films grown in hydride vapor-phase epitaxy by transmission electron microscopy. Properties of III-V nitride compounds; Demonstrations of blue- and ultraviolet-light emitting lasers on GaN-based epitaxial films; Reduction of threading...

  • Vertical strain and doping gradients in thick GaN layers. Siegle, H.; Hoffman, A. // Applied Physics Letters;10/27/1997, Vol. 71 Issue 17, p2490 

    Examines the vertical strain and doping gradients in thick gallium nitride layers. Use of spatially-resolved low temperature luminescence and Raman spectroscopy; Dependence of the peak position of the near band gap luminescence on substrate interface distance; Correlation of observed effects...

  • Spatial variation of luminescence in thick GaN films. Bertram, F.; Srinivasan, S.; Ponce, F. A.; Riemann, T.; Christen, J.; Molnar, R. J. // Applied Physics Letters;2/26/2001, Vol. 78 Issue 9, p1222 

    The spatial variation of the optical properties of hydride vapor-phase epitaxial GaN layers of various thickness has been studied using scanning cathodoluminescence microscopy. A strong improvement of these properties with film thickness is observed in plan view. Cross-sectional studies show a...

  • Disorder-activated infrared modes and surface depletion layer in highly Si-doped hexagonal GaN. Kasic, A.; Schubert, M.; Kuhn, B.; Scholz, F.; Einfeldt, S.; Hommel, D. // Journal of Applied Physics;4/1/2001, Vol. 89 Issue 7 

    Three infrared-active low-polar modes are reported for highly Si-doped hexagonal (α-) GaN. The 0.8-1.6 μm thick films, grown by metal organic vapor phase epitaxy or molecular beam epitaxy on (0001) sapphire substrates, were studied by infrared spectroscopic ellipsometry. For GaN epilayers...

  • Low pressure synthesis of bulk, polycrystalline gallium nitride. Argoitia, Alberto; Hayman, Cliff C. // Applied Physics Letters;1/13/1997, Vol. 70 Issue 2, p179 

    Examines the synthesis of bulk, polycrystalline gallium nitride (GaN) thick films grown at low pressures by direct reaction of atomic nitrogen with liquid gallium. Processes used to confirm the crystals as wurtzitic GaN; Details on band edge peaks and broad yellow band emission values; Efficacy...

  • Development of strain reduced GaN on Si (111) by substrate engineering. Jamil, M.; Grandusky, J. R.; Jindal, V.; Shahedipour-Sandvik, F.; Guha, S.; Arif, M. // Applied Physics Letters;8/22/2005, Vol. 87 Issue 8, p082103 

    We report on a novel scheme of substrate engineering to obtain high-quality GaN layers on Si substrates. Ion implantation of an AlN/Si substrate is performed to create a defective layer that partially isolates the III-nitride layer and the Si substrate and helps to reduce the strain in the film....

  • Cathodoluminescence study of nonuniformity in hydride vapor phase epitaxy-grown thick GaN films. Lee, Woong; Watanabe, Kentaro; Kumagai, Kazuhiro; Park, Seunghwan; Lee, Hyunjae; Yao, Takafumi; Chang, Jiho; Sekiguchi, Takashi // Journal of Electron Microscopy;Feb2012, Vol. 61 Issue 1, p25 

    The nonuniformity in hydride vapor phase epitaxy (HVPE)-grown thick GaN was studied using cathodoluminescence (CL) technique. It was found that the nonuniform luminescence feature originated from pit-type defects. Two kinds of pit-type defects were distinguished by their morphology: one was...

  • Band gap tuning in GaN through equibiaxial in-plane strains. Dong, L.; Yadav, S. K.; Ramprasad, R.; Alpay, S. P. // Applied Physics Letters;5/17/2010, Vol. 96 Issue 20, p202106 

    Structural transformations and the relative variation in the band gap energy (ΔEg) of (0001) gallium nitride (GaN) films as a function of equibiaxial in-plane strains are studied by density functional theory. For relatively small compressive misfits (-6%–0%), the band gap is estimated...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics