Reduction of Dislocation Density in GaAs on Si Substrate by Si Interlayer and Initial Si Buffer Layer

Reduction of the dislocation density in GaAs on Si by the use of a Si interlayer and an initial Si buffer layer is reported. The Si interlayer of 2∼3 monolayers thick was inserted into the GaAs epitaxial layer on a Si substrate by low-temperature Si deposition. Molten KOH etching and cross-sectional transmission electron microscope (XTEM) observations showed a reduction of the dislocation density by 10 -2 ∼10 -3 times at the top surface by the Si interlayer insertion compared to that of conventional growth. An additional reduction of the dislocation density by the initial Si buffer layer grown at 680°C coupled with the interlayer was observed.