Multiscale Materials Modeling Group
Universidad de Valladolid
Project TEC2008-06069, funded by 
A scientific and technological effort is required to continue the down scaling of Si devices which has driven the performance enhancement of integrated circuits and lots of new battery-powered applications. This project focus on the physics and technology involved in dopant incorporation in nanometic Si devices. Many challenges are marked in this field by the International Technology Roadmap for Semiconductors to achieve future technology nodes. Several relevant issues will be addressed in this project. (i) Multi-gate structures, such as FinFETs, are proposed to substitute planar MOS around 2010 to continue the down scaling of Si devices. We will analyze the incorporation of electrically active dopants in such structures. We will pay special attention to issues related to sidewall dopant incorporation, recrystallization of narrow FinFETs and high-temperature implants. (ii) We will study and model the mechanisms of dopant redistribution in amorphous Si, responsibles for dopant diffusion, defect formation, segregation and snow-plow effects as the recrystallization proceeds. These phenomena are relevant because of the use of high implant doses and the advantages of solid-phase epitaxial regrowth for dopant activation. (iii) Leakage currents are affected by the presence of residual defects. We will evaluate the energy levels in the gap related to defects as well as their thermal stability against annealing. (iv) We will evaluate the effectivines of molecular implants in dopant incorporation because of their potential for the formation of ultra-shallow junctions and Si:C layers. For this work we will use a multi-scale simulation scheme. By combining several atomistic techniques (ab-initio, classical molecular dynamics and kinetic Monte Carlo) we will perform fundamental studies of atomic interactions (versus empirical parameter fitting) and we will be able to access to space and time scales of actual technological processes. The overall goal is to provide clues, based on the understanding of physical phenomena involved in the fabrication processes, that lead the optimization of Si technology.