Critical thickness of transition from 2D to 3D growth and peculiarities of quantum dots formation in Ge_xSi_(1-x)/Sn/Si and Ge_(1-y)Sn_y/Si systems

摘要

Highlights•New approach for modeling growth processes of semiconductor compounds is presented.•Decrease in 2D-3D transition temperatures for GeSiSn/Si compared to GeSi/Si is explained.•Dependencies of critical thickness on temperature and composition are explained.•Islands size decreases with increase in deposition rate and decrease of temperature.•The simulated data are in a good agreement with experimentally observed results.AbstractNowadays using of tin as one of the deposited materials in GeSi/Sn/Si, GeSn/Si and GeSiSn/Si material systems is one of the most topical problems. These materials are very promising for various applications in nanoelectronics and optoelectronics due to possibility of band gap management and synthesis of direct band semiconductors within these systems. However, there is a lack of theoretical investigations devoted to the peculiarities of germanium on silicon growth in the presence of tin. In this paper a new theoretical approach for modeling growth processes of binary and ternary semiconductor compounds during the molecular beam epitaxy in these systems is presented. The established kinetic model based on the general nucleation theory takes into account the change in physical and mechanical parameters, diffusion coefficient and surface energies in the presence of tin. With the help of the developed model the experimentally observed significant decrease in the 2D-3D transition temperatures for GeSiSn/Si system compared to GeSi/Si system is theoretically explained for the first time in the literature. Besides that, the derived expressions allow one to explain the experimentally observed temperature dependencies of the critical thickness, as well as to predict the average size and surface density of quantum dots for different contents and temperatures in growth experiment, that confirms applicability of the model proposed. Moreover, the established model can be easily applied to other material systems in which the Stranski–Krastanow growth mode occurs.Graphical abstractDisplay Omitted