Anti-phase boundaries-Free GaAs epilayers on quasi-nominal Ge-buffered silicon substrates

We have obtained Anti-Phase Boundary (APB) free GaAs epilayers on quasi-nominal (001) silicon substrates, while using a thick germanium strain relaxed buffer between the GaAs layer and the silicon substrate in order to accommodate the 4% lattice mismatch between the two. As silicon (001) substrates always have a small random offcut angle from their nominal surface plane, we call them quasi-nominal, We have focused on the influence that this small (<= 0,5 degrees) offcut angle has on the GaAs epilayer properties, showing that it greatly influences the density of APBs, On 0.5' offcut substrates, we obtained smooth, slightly tensile strained (R = 106%) GaAs epilayers that were single domain (e.g., without any APB), showing that it is not necessary to use large offcut substrates, typically 4 to 6', for GaAs epitaxy on silicon, These make the GaAs layers more compatible with the existing silicon manufacturing technology that uses quasi-nominal substrates. (C) 2015 AIP Publishing LLC,