A technique was presented for preparing heteroepitaxial GaAs/Si films having a reduced threading dislocation density. An important factor in this technique was the suppression of 3-dimensional Volmer-Weber island formation during the initial deposition. The suppression was achieved by depositing a stoichiometric GaAs buffer layer, using a migration-enhanced epitaxial technique, onto Si at 348K. Its thickness was greater than the so-called monolithic thickness. Subsequent GaAs films which were deposited, by using conventional molecular beam epitaxy, onto buffer layers which were thicker than the monolithic thickness had superior structural and optical characteristics. The X-ray full-width at half maximum was equal to 110arcsec when the dislocation density at the film surface was 3 x 106/cm2 and the associated 4K photoluminescence full-width at half maximum was equal to 0.0021eV.
Opto-Electronic Device Performance on Reduced Threading Dislocation Density GaAs/Si. P.J.Taylor, W.A.Jesser, J.D.Benson, M.Martinka, J.H.Dinan, J.Bradshaw, M.Lara-Taysing, R.P.Leavitt, G.Simonis, W.Chang, W.W.Clark, K.A.Bertness: Journal of Applied Physics, 2001, 89, 4365-75