Heat Transport across Interfaces for the Optimization of Heat Sinking in Device Applications

Heterogenous integration of materials and devices opens huge opportunities for exploiting device structures which benefit from an optimal combination of electronic and thermal material properties. It is critically important to assess heat transfer across their interfaces to avoid thermal bottlenecks resulting in excessive device temperatures though. Experimental techniques to assess thermal conductivity of materials and thermal boundary resistance between materials are reviewed, with examples from GaN-on-Diamond, diamond to metal diamond composites

Thermal profiles within the channel of planar gunn diodes using micro-particle sensors

The paper describes the use of a novel microparticle sensor (~3 μm diameter) and infra-red (IR) microscopy to measure the temperature profile within the active channel (typically 3 μm length and 120 μm width) of planar Gunn diodes. The method has enabled detailed temperature measurements showing an asymmetrical temperature profile along the active width of these devices. The asymmetrical temperature profile suggests a similar behaviour in the channel current density, which may contribute to the lower than expected RF output power