Thermal Boundary Resistance Reduction by Interfacial Nanopatterning for GaN-on-Diamond Electronics Applications

Area of Science:

• Materials Science
• Solid State Physics
• Electrical Engineering

Background:

• Gallium Nitride (GaN) high electron mobility transistors (HEMTs) offer superior performance for high-power, high-frequency applications.
• Joule self-heating in GaN HEMTs limits their power density and operational lifespan.
• Diamond's exceptional thermal conductivity makes it a promising heat sink material for GaN devices.

Purpose of the Study:

• To investigate strategies for reducing thermal boundary resistance (TBR) at the Gallium Nitride (GaN)/diamond interface.
• To improve heat dissipation in GaN-on-diamond devices for enhanced thermal management.

Main Methods:

• Implementation of nanoscale trenches between Gallium Nitride (GaN) and diamond layers to modify the interface.
• Measurement of thermal properties, specifically effective GaN/diamond TBR (TBR_eff), using nanosecond transient thermoreflectance (ns-TTR).
• Incorporation and annealing of a silicon nitride (SiN) dielectric interlayer to assess its impact on thermal conductivity.

Main Results:

• A 3× reduction in effective GaN/diamond TBR (TBR_eff) was achieved by introducing nanoscale trenches, attributed to increased contact area.
• Annealing the silicon nitride (SiN) dielectric interlayer resulted in a 2× increase in its thermal conductivity, further lowering TBR.
• Demonstrated significant optimization of thermal resistance in heterogeneous interfaces through nanostructuring and annealing.

Conclusions:

• Nanostructured patterning and high-temperature annealing are effective strategies for optimizing thermal resistance at heterogeneous interfaces.
• These advancements pave the way for enhanced thermal management in high-power Gallium Nitride (GaN) device applications.
• Reduced TBR is crucial for maximizing the power density and reliability of advanced electronic devices.