  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.
