Effects of Al0.3Ga0.7As interlayer with pulsed atomic layer epitaxy on heterogeneous integration of GaAs/Ge grown by MOCVD

Abstract In this paper, high quality GaAs films on Ge (0 0 1) substrates with 9° offcut toward the (1 1 1) plane were grown by metal organic chemical vapor deposition (MOCVD) through adopting the Al 0.3 Ga 0.7 As interlayers with pulsed atomic layer epitaxy (PALE) technology. The effects of Al 0.3 Ga 0.7 As PALE interlayers with different growth sequences, AlAs/GaAs PALE and AlGa/AlGaAs PALE, on the morphological, structural and optical properties of GaAs epilayers were investigated. The results showed that Al 0.3 Ga 0.7 As PALE interlayers were preferred to eliminate anti-phase domains (APDs) and suppress Ge atoms outdiffusion at the heterointerface, effectively. Additionally, AlAs/GaAs PALE, the optimized growth sequence of Al 0.3 Ga 0.7 As PALE interlayers, could obtain the smoothest surface morphology (root-mean-square (RMS) 0.43 nm) and best crystalline quality, which was attributed to the control of AsH 3 exposure time ensuring fewer As vacancies acting as defect centers.