Alane adsorption and dissociation on the Si(0 0 1) surface

Area of Science:

• Surface Science
• Computational Materials Science
• Semiconductor Chemistry

Background:

• Understanding the surface chemistry of group III elements on silicon is crucial for semiconductor manufacturing.
• Alane (AlH3) is a potential precursor for aluminum incorporation into silicon, but its decomposition pathway is not fully understood.
• Phosphine (PH3) is a known precursor for phosphorus incorporation, providing a benchmark for comparison.

Purpose of the Study:

• To investigate the energetics and structural evolution of alane decomposition on the Si(001) surface.
• To compare the incorporation behavior of aluminum with that of phosphorus on silicon surfaces.
• To provide insights into the controlled deposition of aluminum for advanced semiconductor applications.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to model the adsorption and decomposition of alane.
• Energetics of various intermediate structures (AlH2, AlH, Al) were calculated.
• Simulated Scanning Tunneling Microscopy (STM) images were generated for key structures.

Main Results:

• Alane forms a dative bond with silicon dimers on the Si(001) surface.
• A significant, gradual decrease in energy was observed during successive dehydrogenation steps.
• The energy for aluminum incorporation into the surface, displacing a silicon atom, is comparable to that of aluminum adatoms.

Conclusions:

• Aluminum incorporation into the Si(001) surface is energetically feasible and likely controllable.
• The control over aluminum incorporation is comparable to, though slightly more challenging than, phosphorus incorporation.
• These findings support the potential for precise control in fabricating advanced semiconductor materials using alane.