Evaluation of the effect of the dislocation loops and misfit dislocations on the Ge distribution in the SiGe/Si film
Abstract
Evaluation of the effect of the dislocation loops and misfit dislocations on the Ge distribution in the SiGe/Si film
Incoming article date: 28.11.2016Solved calculation of equilibrium distribution of Ge and the density of elastic energy in semiconductor film SiGe/Si. Built the 3D model of flat film with pyramid islands and dislocations. Calculation of elastic deformation is made using the finite element method. In this model takes into account the uneven distribution of Si and Ge due to threading dislocations, misfit stress and dislocation loops. The results showed that in the two-part elastic layer SiGe provision balance dislocation is located in the depth of the inconsistencies of the film and not on the boundary of film-substrate. This conclusion applies to the penetrating dislocation, while changing the orientation of dislocation much changes box elastic stresses and distribution component of Si and Ge in the film. The results of the calculation model of the sample, including prismatic dislocation loop, shown a significant impact on the value of the elastic energy of the film. While accounting for the effects of non-uniform distribution of SiGe alloy component does not result in a significant change in the magnitude of elastic energy model and critical values of height. According to calculations, taking into account the heterogeneity of the distribution component of the alloy transition to the formation of Epitaxial islets on the film surface occurs at lower values of their critical size, especially when small concentrations of Ge in the alloy. The results of calculation of the elastic energy of the film received at work, can be applied to calculate the conditions of occurrence of defects in nanometer dimension on the original flat free surface of semiconductor films.
Keywords: germanium, thin film, heteroepitaxy, SiGe, misfit dislocations, threading dislocation, elastic energy density, dislocation loop