A Critical Review of Thermal Boundary Conductance across Wide and Ultrawide Bandgap Semiconductor Interfaces

Abstract

The emergence of wide and ultrawide bandgap semiconductors has revolutionized the advancement of next-generation power, radio frequency, and opto- electronics, paving the way for chargers, renewable energy inverters, 5G base stations, satellite communications, radars, and light-emitting diodes. However, the thermal boundary resistance at semiconductor interfaces accounts for a large portion of the near-junction thermal resistance, impeding heat dissipation and becoming a bottleneck in the devices’ development. Over the past two decades, many new ultrahigh thermal conductivity materials have emerged as potential substrates, and numerous novel growth, integration, and characterization techniques have emerged to improve the TBC, holding great promise for efficient cooling. At the same time, numerous simulation methods have been developed to advance the understanding and prediction of TBC. Despite these advancements, the existing literature reports are widely dispersed, presenting varying TBC results even on the same heterostructure, and there is a large gap between experiments and simulations. Herein, we comprehensively review the various experimental and simulation works that reported TBCs of wide and ultrawide bandgap semiconductor heterostructures, aiming to build a structure–property relationship between TBCs and interfacial nanostructures and to further boost the TBCs. The advantages and disadvantages of various experimental and theoretical methods are summarized. Future directions for experimental and theoretical research are proposed.

Inversion for Thermal Properties with Frequency Domain Thermoreflectance

“…Converted to TBC, these values are less than 10 MW/m 2 ·K, greater than 100, and 10–100 MW/m 2 ·K. These ranges agree with the values reported in Tables and , as well as with values reported in existing literature . While deviations exist in the partially bonded regions, the inversions using sparse and dense measurement data show good agreement, suggesting an accurate inversion.…”

“…Inferred thermal conductivity along the measurement line is shown in Figure 6a 1 and 2, as well as with values reported in existing literature. 43 While deviations exist in the partially bonded regions, the inversions using sparse and dense measurement data show good agreement, suggesting an accurate inversion.…”

Phonon dynamic behaviors induced by amorphous layers at heterointerfaces

“…A detailed description of the annealing technique can be found in ref. 57. In our simulations, we interestingly found that the amorphous structure preferentially converted into a rocksalt phase instead of the initialized wurtzite phase, as shown in Fig.…”

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

“…To enhance heat dissipation, silicon carbide (SiC) has been utilized as a substrate due to its high thermal conductivity (∼350 W m –1 K –1 ) and relatively close lattice constant to GaN. However, the GaN/SiC interface typically exhibits limited thermal boundary conductance (TBC), , preventing the full utilization of the high thermal conductivity substrate . Consequently, numerous experimental and theoretical studies have been conducted to investigate and enhance thermal transport across GaN/SiC interfaces. − …”