<i>In situ</i> monitoring of strain relaxation during antimony-mediated growth of Ge and Ge<i>1−y</i> C<i>y</i> layers on Si(001) using reflection high energy electron diffraction

Abstract

Ge and Ge0.99C0.01 layers were grown pseudomorphically on Si(001) and investigated during growth with reflection high energy electron diffraction (RHEED). We show that the RHEED technique permits dynamic monitoring of the in-plane lattice spacing of the growing layer by measuring the distances between diffraction features during growth and applying an appropriate mathematical algorithm. The onset of plastic relaxation in these layers as a function of growth temperature was investigated. Lower growth temperature increases the critical layer thickness. We estimated an overall activation energy of around 0.1 eV. Adding 1% carbon to the Ge layer delays the onset of relaxation. But the Ge1−yCy layer does not behave identically to a pseudomorphic Ge film with an artificially reduced strain. It should rather be considered as a new material.