Thermal Rounding Kinetics and Demonstration of Steep and Flat Facets Succession in Selective Si-Based Epitaxy

Abstract

In the first part of this work, a quantitative study of rounding kinetics in Si1-xGex (SiGe) epitaxies on patterned wafers is shown. A perfect screening of different patterns’ morphological evolution during annealing is performed by AFM. This allows the kinetics to be quantified by measuring the displaced volume of matter during the annealing. Two energies are extracted: 7.1eV between 650°C and 675°C and 1.2eV between 675°C and 700°C. The second part deals with the behavior of Si-based caps deposited on a non-flat surface. Different caps (Si vs SiGe) of different thicknesses were used. Both caps do not behave in the same way since SiGe caps are more efficient to flatten the rounded surface and obtain a “standard” morphology as if it was deposited on a perfectly flat surface. This is not the case for Si which makes a succession of terraces when deposited on such a surface.