Grown-in beryllium diffusion in indium gallium arsenide: An ab initio, continuum theory and kinetic Monte Carlo study

TL;DR

This study combines ab initio calculations, continuum theory, and kinetic Monte Carlo simulations to model beryllium diffusion in InGaAs, revealing dominant kick-out mechanisms and the significant roles of Ga, In, and As interstitials.

Contribution

It introduces a comprehensive multi-scale model that explains anomalous Be diffusion in InGaAs, incorporating detailed atomic interactions and migration mechanisms.

Findings

Kick-out reactions dominate Be diffusion in InGaAs.

Ga and In interstitials have different roles in diffusion.

As influence on Be diffusion may be significant.

Abstract

A roadblock in utilizing InGaAs for scaled-down electronic devices is its anomalous dopant diffusion behavior; specifically, existing models are not able to explain available experimental data on beryllium diffusion consistently. In this paper, we propose a comprehensive model, taking self-interstitial migration and Be interaction with Ga and In into account. Density functional theory (DFT) calculations are first used to calculate the energy parameters and charge states of possible diffusion mechanisms. Based on the DFT results, continuum modeling and kinetic Monte Carlo simulations are then performed. The model is able to reproduce experimental Be concentration profiles. Our results suggest that the Frank-Turnbull mechanism is not likely, instead, kick-out reactions are the dominant mechanism. Due to a large reaction energy difference, the Ga interstitial and the In interstitial play different roles in the kick-out reactions, contrary to what is usually assumed. The DFT calculations also suggest that the influence of As on Be diffusion may not be negligible.