A NEW GAAS ON SI STRUCTURE USING ALAS BUFFER LAYERS GROWN BY ATOMIC LAYER EPITAXY

We have developed a new GaAs on Si structure with a thin AlAs buffer layer which was grown by atomic layer epitaxy (ALE). The characteristics of two types of ALE layers, GaAs and AlAs, were studied. We have found that single crystals of GaAs and AlAs layers can be grown directly onto Si substrates. Even though the growth was initiated by the formation of three-dimensional islands, AlAs layer growth changed from three-dimensional to two-dimensional at an earlier stage than that of GaAs layers. The morphology and quality of the ALE buffer layers are markedly improved by initiating the growth from AlAs. The characterization of GaAs layers grown by metalorganic vapor phase epitaxy on ALE layers indicates that the ALE-AlAs buffer layer will help improve the quality of GaAs on Si. © 1990.