Multiscale Materials Modeling Group
Universidad de Valladolid
Project TEC2011-27701, funded by 
This project deals with radiation-induced defects in semiconductors, and in particular in silicon. We will focus on relevant defects for radiation detectors, those generated by ion implantation for junction formation of Si devices, and those optically active. In spite of the effort devoted up to now by the scientific community there are a lot of aspect not claried, and a global understanding becomes increasingly important to optimize the devices. Although differences in the mass, energy, dose of the radiation differ in each application, many of the generated defects are alike in all cases. Models developed in one context can be used and even introduce new perspectives to other applications. The goal of this project is to provide the theoretical understanding for the correlation between microscopic radiation-induced defects and their macroscopic effects, mainly related to electrical and optical characteristics. The gain in the understanding of the defect structure and properties will be applied to help spectroscopic characterization techniques (to link lines to defects) and to design defect engineering strategies in order to minimize detrimental effects and enhance the beneficial properties. In this work we will use a multi-scale simulation scheme in which we combine ab-initio, molecular dynamics (MD) and Monte Carlo (MC) techniques. We will use MD to identify the morphology of relevant defects with speciall focus on small amorphous defects. Electrical and optical characteristics will be evaluated with ab-initio techniques. The information provided by both techniques will be used to improve MC models. Using MC we will reproduce macroscopic radiation conditions in order to obtain clues that lead defect engineering strategies for the hardening of radiation detectors, the minimization of device leakage currents due to ion implantation processes and the controled introduction of defects with optical properties.