Thermal impedance measurements under non-equilibrium conditions. How to extend its validity

摘要

Thermal impedance measurement of semiconductor devices is much easier to perform experimentally when heating and measuring phases are performed separately in order to avoid mutual interference. However, unless we are able to guarantee that the system is in thermal equilibrium before performing the measurement, the result is not consistent with the definition of thermal impedance. This work presents a method to extend the validity of a measurement made under non-equilibrium conditions to fit the real value of thermal impedance, under the assumption that the system is linear or has negligible nonlinearity, i.e. the parameters involved can be considered nearly independent of temperature.