Remote epitaxy of InxGa1-xAs (001) on graphene covered GaAs (001) substrates

The heteroepitaxial growth of lattice mismatched layers is crucial for modern semiconductor device fabrication, but it is a significant challenge in epitaxy. Growth of lattice mismatched materials creates strain in the epitaxial layer, which is usually relaxed by introducing crystal defects deteriorating the device performance. Remote epitaxy on graphene covered substrates was recently proposed to offer a different relaxation pathway for the strained films. Here, we report on the remote heteroepitaxy growth by molecular beam epitaxy (MBE) of InxGa(1-x)As-layers (0 < x <= 0.5) on transfer graphene covered GaAs-(001) substrates. We show that a carefully optimized plasma treatment followed by ultra-high vacuum (UHV) annealing allows InxGa(1-x)As remote epitaxy on transfer graphene covered GaAs substrates. Detailed investigations on the strain relaxation of 200 nm thick InxGa(1-x)As-layers on graphene covered GaAs and for comparison on bare GaAs are presented. High-resolution X-ray -diffraction (HRXRD) and transmission electron microscopy (TEM) measurements reveal single crystalline growth on large areas. On bare GaAs we observe the well-known tilt of the InxGa(1-x)As-layers whereas on graphene no tilt is observed. The layers grown on graphene are more relaxed than layers grown on bare GaAs and their strain relaxation is symmetric whereas on bare GaAs the strain relaxation is stronger along the [110] direction.

Automated summary

This study reports on the remote heteroepitaxy growth of InxGa(1-x)As-layers on transfer graphene covered GaAs substrates by molecular beam epitaxy. The strain relaxation of the layers on graphene was compared to that on bare GaAs, revealing more relaxation and symmetric strain relaxation on graphene.