Nucleation and initial growth of GaAs on Si substrate

The microstructure of thin layers of GaAs grown on Si substrates at low growth temperatures by molecular beam epitaxy was examined using transmission electron microscopy and MeV 4He+ ion channeling angular scan analysis. Crystalline island formation is observed at temperatures as low as 325 °C, with epitaxial orientation and distinct nucleation habits apparently tied to the symmetry of the misoriented substrate. For films with no exposure to temperatures above 405 °C, the planar strain is found to be compressive, up to a thickness of 100 nm.