Structural investigation of MOVPE-Grown GaAs on Ge by X-ray techniques
Wong, Chiu Soon and Bennett, N. S. and Galiana, B. and Tejedor, P. and Benedicto, M. and Molina Aldareguia, J. M. and McNally, P. J. (2012) Structural investigation of MOVPE-Grown GaAs on Ge by X-ray techniques. Semiconductor Science and Technology, 27 (11). p. 115012. ISSN 0268-1242
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The selection of appropriate characterisation methodologies is vital for analysing and comprehending the sources of defects and their influence on the properties of heteroepitaxially grown III-V layers. In this work we investigate the structural properties of GaAs layers grown by Metal-Organic Vapour Phase Epitaxy (MOVPE) on Ge substrates – (100) with 6⁰ offset towards <111> – under various growth conditions. Synchrotron X-ray topography (SXRT) is employed to investigate the nature of extended linear defects formed in GaAs epilayers. Other X-ray techniques, such as reciprocal space mapping (RSM) and triple axis ω-scans of (00l)-reflections (l = 2, 4, 6) are used to quantify the degree of relaxation and presence of antiphase domains (APDs) in the GaAs crystals. The surface roughness is found to be closely related to the size of APDs formed at the GaAs/Ge heterointerface, as confirmed by X-ray diffraction (XRD), as well as atomic force microscopy (AFM), and transmission electron microscopy (TEM).
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