Comparison of Different Cooling Schemes for AlGaN/GaN High-Electron Mobility Transistors

Area of Science:

• Materials Science
• Thermal Engineering
• Semiconductor Devices

Background:

• Effective thermal management is critical for the performance and reliability of Aluminum Gallium Nitride/Gallium Nitride (AlGaN/GaN) high-electron mobility transistors (HEMTs).
• Various cooling schemes exist, each with unique advantages and limitations impacting thermal resistance.

Purpose of the Study:

• To compare the cooling performance of three distinct schemes: remote cooling (R-cool), near-chip cooling (NC-cool), and chip-embedded cooling (CE-cool) for AlGaN/GaN HEMTs.
• To investigate the impact of geometric parameters and operating conditions on the thermal resistance of these cooling methods.

Main Methods:

• Comparative analysis of R-cool, NC-cool, and CE-cool.
• Investigation of thermal resistance variations based on microchannel base thickness (h), heat source pitch (P), substrate thermal conductivity (λ), and convective heat transfer coefficient (h).

Main Results:

• NC-cool and CE-cool exhibit comparable thermal resistances.
• Decreasing microchannel base thickness (h) significantly increases CE-cool's thermal resistance, making NC-cool superior below a critical thickness.
• Critical thickness is influenced by heat source pitch (P), convective heat transfer coefficient (h), and substrate thermal conductivity (λ).
• Increased P or λ improves thermal resistance across all three schemes.
• Increased h significantly reduces thermal resistance for NC-cool and CE-cool, with minimal impact on R-cool.

Conclusions:

• The choice between NC-cool and CE-cool depends critically on microchannel base thickness, heat source pitch, and substrate properties.
• Optimizing geometric parameters and material properties is essential for effective thermal management in AlGaN/GaN HEMTs.