Effect of the Al0.3Ga0.7As interlayer thickness upon the quality of GaAs on a Ge substrate grown by metal-organic chemical vapor deposition

Abstract

GaAs epilayers on Ge substrates are grown with a thin Al0.3Ga0.7As interlayer via metal-organic chemical vapor deposition with the goal of investigating the effect of the Al0.3Ga0.7As interlayer thickness upon the GaAs epilayer. The results show that as the Al0.3Ga0.7As interlayer thickness increases from 0 to 30 nm, both the crystal quality and surface morphology of the GaAs epilayer follow a trend of melioration and then deterioration. All of the Al0.3Ga0.7As interlayers investigated are seen to effectively block the diffusion of Ge atoms to the GaAs epilayers, and high crystalline quality GaAs epilayers with a smooth surface are obtained by growing a 15–23 nm-thick Al0.3Ga0.7As interlayer.