Relation Between Complex Permittivity and Microwave Heating for Semiconductor Materials

The microwave heating depends on the complex permittivity of the material, in particular the dielectric loss factor of the imaginary part. It has been found that there is a positive correlation between the loss factor and microwave heating in semiconductor materials such as LED and GaN. Further, we measured the permittivity and electric conductivity of Si substrates of different types, and then the relationship between these properties and microwave heating was investigated. As a result, it became clear that there is a resistivity (or electrical conductivity) at which the loss factor becomes the maximum, and an extremely high-speed heating of 100 °C/s or over was achieved under optimum heating condition.