Details

Autor(en) / Beteiligte

• Dimitrakopulos, G.P.
• Bazioti, C.
• Grym, J.
• Gladkov, P.
• Hulicius, E.
• Pangrác, J.
• Pacherová, O.
• Komninou, Ph

Titel

Misfit dislocation reduction in InGaAs epilayers grown on porous GaAs substrates

Ist Teil von

• Applied surface science, 2014-07, Vol.306, p.89-93

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2014

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •InxGa1−xAs epilayers were grown by MOVPE on porous GaAs substrates.•The porous substrates led to significant reduction of misfit dislocation density.•Epilayers retained more elastic strain compared to growth on nonporous GaAs.•The pores acted as the nucleation sites for glissile 60° dislocations. Elastic accommodation of heteroepitaxial layers beyond their critical thickness is crucial for the reduction of misfit dislocations. One approach is to utilize substrate engineering in order to delay plastic relaxation. In this work, pore networks were introduced electrochemically in GaAs substrates in order to modify their mechanical responses. InxGa1−xAs epilayers with nominal indium contents up to x=0.20 were then deposited by MOVPE, and were compared to similar epilayers grown on nonporous GaAs. Strain relaxation and defect introduction were studied by TEM observations, x-ray diffraction, and photoluminescence measurements. It was found that the porous substrates acted to reduce the density of misfit dislocations, thereby increasing the epilayer critical thickness. The InGaAs epilayers retained a significantly higher amount of elastic strain compared to ones grown on nonporous GaAs. The onset of plasticity was mediated by the pores, which acted as nucleation sites for 60° dislocations that glided toward the interface.