The initial stage of GaAs epitaxial growth on Si(100) has been studied by RHEED and AES. On exposure to a As4 flux, the Si surface is covered with one or two monolayers of As which are stable up to 700°C, while Ga on Si desorbs even at 500°C. There are two kinds of Si-As reconstruction, which depend on the temperature of Si exposed to As4 flux. One is 1×2 for high temperature (>600°C) and the other is 2×1 for low temperature (<450°C) when the Si substrate has 2×1 reconstruction. The surface reconstructions of GaAs grown on Si(100)-As 1×2 and Si(100)-As 2×1 are perpendicular to each other, which indicates that the domain direction of GaAs to Si substrate is different depending on the initial growth temperature.

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The nucleation and growth process of GaAs on Si has been studied by auger electron spectroscopy and transmission electron microscopy. At growth temperatures above 120°C, epitaxial growth begins with island formation, the size of which depends on the growth temperature. At low growth temperature(∼120°C) the epitaxial islands grow preferentially on Si surface terraces rather than on steps, and misfit dislocations are introduced at steps where the leading edges of growing islands come into contact with each other.

The origin of the formation of a highly resistive layer around a growth-interrupted interface in GaAs has been studied by capacitance-voltage carrier profiling and deep-level transient spectroscopy. It is concluded that the origin of the highly resistive layer is attributable to the formation of interface states created by exposure of the GaAs surface to air. The Fermi level at the interface is pinned in n-type GaAs, but is not in p-type GaAs.

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