Strain engineered segregation regimes for the fabrication of thin Si1-xGex layers with abrupt n-type doping

We implement a low temperature LT growth technique for achieving abrupt n-type doping profiles in order to match the vertical scaling of modulation doped field effect transistor fully depleted structures. We use strain engineering of Ge rich Si1−xGex layers at LTs to suppress dopant segregation and to fully incorporate antimony in ultrathin Si1−xGex layers. We show that, only in the LT terrace-mediated kinetically limited regime, segregation is controlled by strain. At higher temperatures, in the step-edge mediated kinetically limited regime, segregation becomes independent of strain and at even higher temperatures, segregation follows the classical equilibrium behaviour mainly controlled by reduction of surface energy and not by strain.