Anomalous impurity segregation and local bonding fluctuation in l-Si

Area of Science:

• Materials Science
• Semiconductor Physics
• Physical Chemistry

Background:

• Anomalous impurity redistribution is frequently observed in group-IV elements post-laser irradiation.
• The underlying mechanisms for this phenomenon remain largely unexplained in scientific literature.
• The peculiar bonding characteristics of liquid group-IV semiconductors are hypothesized to play a role.

Purpose of the Study:

• To correlate anomalous impurity redistribution with the bonding nature of liquid group-IV semiconductors.
• To investigate the diffusion transport of boron (B) in liquid silicon (l-Si) under various experimental conditions.
• To propose and validate a microscopic diffusion model explaining the observed segregation behavior.

Main Methods:

• Analysis of the Boron-Silicon (B-Si) system across a broad spectrum of experimental conditions.
• Development of a diffusion model based on the balance between impurity states with differing bonding configurations and diffusivities.
• Comparison of experimental chemical profiles with simulation results to validate the proposed model.

Main Results:

• Demonstration that the anomalous redistribution of Boron in liquid Silicon is due to non-Fickian diffusion.
• Identification of two distinct impurity states in liquid silicon, each with a different migration speed.
• Accurate validation of the proposed diffusion model through detailed comparisons with experimental data.

Conclusions:

• The study elucidates the microscopic mechanism behind anomalous impurity redistribution in laser-irradiated group-IV elements.
• The proposed model, based on dual impurity states and non-Fickian diffusion, successfully explains Boron segregation in liquid silicon.
• This work provides a validated framework for understanding impurity behavior in liquid semiconductors.