Growth of GaAs on Si by Using a Thin Si Film as Buffer Layer

We report a novel technique for growing high-quality GaAs on Si substrate. The process involves deposition of a thin amorphous Si film prior to the conventional two-step growth. The GaAs layers grown on Si by this technique using metalorganic chemical vapor deposition exhibit a better surface morphology and higher crystallinity as compared to the samples grown by conventional two-step method. The full width at half maximum (FWHM) of the x-ray (004) rocking curve for 2.2 μm thick GaAs/Si epilayer grown by using this new method is 160arcsec. The FWHM of the photo-Luminescence spectrum main peak for this sample is 2.1 meV. These are among the best results reported so far. In addition, the mechanism of this new growth method was studied using high-resolution transmission electron microscopy.