Thermal Profiles Within the Channel of Planar Gunn Diodes Using Micro-Particle Sensors

This letter describes the use of a novel micro-particle sensor (~3 μm diameter) and infra-red 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 behavior in the channel current density, which may contribute to the lower than expected RF output power.