Robust Thermal Transport across the Surface-Active Bonding SiC-on-SiC

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Surface-active bonding (SAB) is a key technique for direct semiconductor bonding.
• Interlayer properties and reduced thickness in SAB can impact thermal transport.
• Understanding thermal behavior is critical for advanced semiconductor devices.

Purpose of the Study:

• To investigate the temperature-dependent thermal conductivity of 4H-SiC thin films.
• To measure the effective thermal boundary resistance (TBR_eff) of SiC-on-SiC interfaces formed by SAB.
• To analyze the impact of TBR_eff on device thermal management.

Main Methods:

• Multiple-probe wavelength nanosecond transient thermoreflectance (MW-TTR) for thermal measurements.
• Density functional theory (DFT) calculations incorporating four-phonon scattering.
• Molecular dynamics (MD) simulations for interface analysis.
• 2D finite element simulations to assess thermal effects.

Main Results:

• Measured thermal conductivity of 4H-SiC thin films agrees well with DFT, highlighting the importance of four-phonon scattering at high temperatures.
• A small but non-zero TBR_eff was measured for SAB SiC-on-SiC interfaces.
• SAB process forms a strong interface with an extremely thin interlayer.
• TBR_eff significantly impacts maximum device temperature (T_max) by at least 19 °C.

Conclusions:

• Four-phonon scattering is critical for 4H-SiC thermal conductivity in high-temperature applications.
• SAB creates robust SiC-on-SiC interfaces with minimal thermal resistance.
• Accurate thermal transport characterization is essential for optimizing SAB processes and thermal management in SiC devices.