# Alane adsorption and dissociation on the Si(001) surface

## TL;DR

This study uses DFT calculations to analyze how alane decomposes and interacts with the Si(001) surface, revealing insights into its bonding, energetics, and potential for controlled surface incorporation, comparable to phosphorus.

## Contribution

It provides the first detailed computational analysis of alane adsorption, dissociation pathways, and surface incorporation energetics on Si(001), highlighting its potential for precise surface doping.

## Key findings

- Alane forms a dative bond with silicon dimers.
- Dehydrogenation of AlH3 on Si(001) is energetically favorable.
- Al atoms can be incorporated into the surface similarly to P atoms.

## Abstract

We used DFT to study the energetics of the decomposition of alane, AlH3, on the Si(001) surface, as the acceptor complement to PH3. Alane forms a dative bond with the raised atoms of silicon surface dimers, via the Si atom lone pair. We calculated the energies of various structures along the pathway of successive dehydrogenation events following adsorption: AlH2, AlH and Al, finding a gradual, significant decrease in energy. For each stage, we analyse the structure and bonding, and present simulated STM images of the lowest energy structures. Finally, we find that the energy of Al atoms incorporated into the surface, ejecting a Si atom, is comparable to Al adatoms. These findings show that Al incorporation is likely to be as precisely controlled as P incorporation, if slightly less easy to achieve.