Comparison of different grading schemes in InGaAs metamorphic buffers on GaAs substrate: Tilt dependence on cross-hatch irregularities

• Published in: Applied surface science Vol. 357; pp. 922 - 930
• Main Authors: Kumar, Rahul, Bag, Ankush, Mukhopadhyay, Partha, Das, Subhashis, Biswas, Dhrubes
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2015
• Subjects: Atomic force microscopy; Camber; Cross-hatch; Gallium arsenide; Gallium arsenides; Grading; Irregularities; Metamorphic; Metamorphic buffer; Residual strain; Roughness; Tilt; Residual strain; Tilt; Cross-hatch; Metamorphic buffer; Roughness
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.09.145

•InGaAs graded MBs with different grading scheme has been grown by MBE on GaAs.•Continuously graded MB exhibits smoother surface morphology.•Grading scheme has been found to have little impact on lattice relaxation.•Grading schemeaffects the lattice tilt significantly.•Cross-hatch surface irregularities affect the crystallographic tilt.
InGaAs graded metamorphic buffers (MBs) with different grading strategies have been grown by molecular beam epitaxy (MBE) on GaAs (001) substrate. A detailed comparative analysis of surface using atomic force microscopy (AFM), and bulk properties using high resolution X-ray diffraction (HRXRD) and room temperature photoluminescence (RTPL) of grown MBs have been presented to comprehend the effectiveness of different grading scheme on InGaAs MBs. Conventional, statistical and fractal analysis on measured AFM data has been performed for in-depth investigation of these surfaces. The grading scheme has been found to have little impact on residual strain while it affects the epitaxial tilt significantly. Moreover, the tilt has been found to depend on growth front irregularities. Tilt magnitude in a graded MB has been found to vary with composition while tilt azimuth has been found to be almost same in the graded layers. PL Intensity and a shift in the PL peaks have been used to study the quality of the MB and residual strain comparatively.