Effectiveness of InGaAs/GaAs superlattice dislocation filter layers epitaxially grown on 200 mm Si wafers with and without Ge buffers

Low threading dislocation density (TDD) in GaAs epitaxial layers grown on silicon substrate (e.g. TDD < 10(6)cm(-2)) is critical for GaAs-based optoelectronic and high-performance electronic devices on silicon. Ge buffers and InxGa1-xAs/GaAs superlattice layers (SLs) are commonly used to reduce the TDD in GaAs epitaxial layers grown on Si wafers. In previous reports, TDD of similar to 10(7)cm(-2)in GaAs and InGaP layers grown on 200 mm Si wafers was achieved by using Ge buffers only (e.g. Wanget al2017Semicond. Sci. Technol.32125013) and TDD of similar to 10(6)cm(-2)in GaAs epi-layers for quantum dot lasers on Si was achieved by using SL insertion layers (e.g. Shanget al2019IEEE J. Sel. Top. Quantum Electron.251502207). In this work, the effectiveness of the dislocation filtering effect of InxGa1-xAs/GaAs SLs combined with Ge buffers is investigated. The results are compared with wafers where InxGa1-xAs/GaAs SLs were directly grown on GaAs-on-Si buffers without Ge buffers. The InxGa1-xAs/GaAs dislocation filter layers (DFLs) consisted of 10 nm InxGa1-xAs/10 nm GaAs layers superlattice spaced by GaAs layer. Then, 1000 nm thick InGaP layers were grown on top of the DFLs to characterize the effect. Transmission electron microscopy, etch-pit density, x-ray diffraction, and photoluminescence were performed to characterize the quality of the materials. Our results indicate that for the growth with Ge buffers there was no significant difference in the final TDDs in the InGaP layers compared with a reference wafer that did not have DFL. For the growth without Ge buffers, the dislocation filtering effect was indeed observed, although it was not as significant as in other reports. For all wafers with DFLs, large wafer bow and dense film cracks appeared, which hinders the practical application of this method.