Enhanced reduction in threading dislocation density in Ge grown on porous silicon during annealing due to porous buffer reconstruction

Year: 2016

Authors: Calabrese G., Baricordi S., Bernardoni P., De Salvador D., Ferroni M., Guidi V., Morandi V., Vincenzi D.

Autors Affiliation: Univ Ferrara, Dept Phys & Earth Sci, I-44122 Ferrara, Italy;‎ Univ Padua, Dept Phys & Astron, I-35131 Padua, Italy;‎ Univ Brescia, Dept Informat Engn, CNR, INO,Sensor Lab, I-25123 Brescia, Italy;‎ CNR, IMM, I-40129 Bologna, Italy

Abstract: We investigated the effect of annealing on the crystalline quality of Ge epilayers grown on low porosity porous silicon (pSi) buffer layer and on bulk Si by LEPECVD. High-resolution XRD analysis indicates that during annealing, Ge grown on pSi undergoes a stronger reorganization compared to Ge grown on Si in terms of strain distribution and mosaic broadening. Strong morphological reorganization of the pSi buffer during annealing leads to a stronger reduction in Ge mosaicity as compared to annealed Ge on bulk Si. This improvement is attributed to bending of threading dislocations in a plane parallel to the growth interface, which is attributed to a strain field introduced by pSi within Ge during their simultaneous reorganization at high-temperature. After cyclic annealing at 750 degrees C, plan view transmission electron microscopy analysis revealed a threading dislocation density for Ge on pSi which is about one order of magnitude smaller than for annealed Ge on bulk Si. Ge on pSi virtual substrates thus represent a promising platform for the growth of III-V and GeSn semiconductors on Si with a low cost and high-throughput technique. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


Volume: 213 (1)      Pages from: 96  to: 101

KeyWords: annealing; dislocations; epitaxy; germanium; porous materials; silicon
DOI: 10.1002/pssa.201532427

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