Universidad de Valladolid

Universidad de Valladolid

Atomistic modeling of high energy irradiation in semiconductors

Project PID2020-115118GB-I00, funded by Logo MCI

Irradiation in semiconductors plays a key role both in the fabrication of devices, through the ion implantation process, and during their operation (medical use, aerospace applications, high energy physics, etc.). Modeling of interactions between energetic particles and atoms in irradiated semiconductors allows to guide the design of devices with improved performance and higher resistance to radiation during their operation. The increasing technological demands are hindered by the capabilities of existing modeling, and have unveiled physical phenomena of high scientific interest. In particular, high energy implantations of arsenic required to create deep wells in CMOS Image Sensing Devices have revealed scattering processes and energetic losses that are still not correctly described. In addition, irradiation with high energy hadrons shows an effective loss of dopants whose microscopic origin is still unknown. The need of improved models for high energy irradiation in Si motivates this research proposal, which will be carried out by the Multiscale Materials Modeling group at the University of Valladolid.

The aim of this project is the development of a unified model of irradiation in semiconductors, physically based and computationally efficient. This predictive model will be applicable to practical problems in a wide range of irradiation conditions, extending models and simulations tools to the range of tens of MeV. Our proposal is based on the improvement of Monte Carlo models within the Binary Collision Approximation. It relies on previously developed theories, on more fundamental atomistic simulations to identify and quantify the underlying physical phenomena, and on experimental data to test the models.

This project will address subjects such as

  1. modeling of electronic excitation effects on crystalline lattice stability,
  2. improvement of the atomistic description of light energetic particles induced recoils,
  3. formulation of interactions between boron and impurities (oxygen, carbon) triggered by irradiation induced defects, and
  4. implementation of efficient computational strategies.
Although we will focus mainly on silicon, this project will make progress on the understanding and quantification of high energy irradiation effects in different materials. Besides, this project will contribute to the technological advance for the fabrication of infrared image sensors and radiation hard devices, together with other implications in the development of future processes and devices.