Enhanced Thermal Boundary Conductance across GaN/SiC Interfaces with AlN Transition Layers

Area of Science:

• Materials Science
• Solid State Physics
• Semiconductor Devices

Background:

• Effective heat dissipation is critical for the performance and reliability of high-power Gallium Nitride (GaN)-based electronics.
• Aluminum Nitride (AlN) transition layers are frequently used in GaN-on-Silicon Carbide (SiC) substrate growth, but their effect on thermal transport at the GaN/SiC interface is not fully understood.

Purpose of the Study:

• To experimentally measure the thermal boundary conductance (TBC) across GaN/SiC interfaces with varying AlN transition layer thicknesses.
• To investigate the influence of AlN layers on the crystalline quality of GaN and its impact on interfacial thermal transport.
• To elucidate the mechanisms behind the observed changes in TBC using molecular dynamics simulations.

Main Methods:

• Experimental measurement of TBC across GaN/SiC interfaces with AlN layers (0-73 nm) at various temperatures.
• Structural characterization techniques to assess GaN crystalline quality.
• Molecular dynamics simulations employing deep learning-based interatomic potentials.

Main Results:

• The addition of an AlN transition layer significantly increases the TBC of the GaN/SiC interface, especially at higher temperatures.
• AlN layers improve the crystalline quality of the GaN layer near the interface.
• Simulations confirm the experimental TBC enhancement, even for atomically perfect interfaces, suggesting a 'phonon bridge' effect.

Conclusions:

• AlN transition layers are beneficial for enhancing thermal transport across GaN/SiC interfaces in high-power electronics.
• The improved TBC is attributed to a combination of enhanced crystalline quality and the phonon-mediating role of the AlN layer.
• These findings provide crucial insights for optimizing thermal management in GaN-based devices.