Growth of InGaAs nanowires on Ge(111) by selective-area metal-organic vapor-phase epitaxy

•Growth of InGaAs NWs on Ge(111) was achieved by selective-area MOVPE.•Formation of (111)B polarity on non-polar Ge(111) was a key to vertical NW growth.•Percentage of vertical NWs was improved by changing the partial AsH3 pressure.•The yield of vertical NWs was achieved over 90% by optimization of FME cycles.•We characterized the InGaAs NW by EDX line-profile and heterointerface of InGaAs/Ge by TEM.

We report the growth of InGaAs nanowires (NWs) on Ge(111) substrates using selective-area metal-organic vapor-phase epitaxy (SA-MOVPE) for novel InGaAs/Ge hybrid complementary metal-oxide-semiconductor (CMOS) applications. Ge(111) substrates with periodic arrays of mask opening were prepared, and InGaAs was selectively grown on the opening region of Ge(111). A uniform array of InGaAs NWs with a diameter around 100 nm was successfully grown using appropriate preparation of the initial surfaces with an AsH3 thermal treatment and flow-rate modulation epitaxy (FME). We found that optimizing partial pressure of AsH3 and the number of FME cycles improved the yield of vertical InGaAs NWs. Line-scan profile analysis of energy dispersive X-ray (EDX) spectrometry showed that the In composition in the InGaAs NW was almost constant from the bottom to the top. Transmission electron microscope (TEM) analysis revealed that the interface between InGaAs NW and Ge had misfit dislocations, but their distance was longer than that expected from the difference in their lattice constants.