Issues of Using Unsaturated Heating Time for Transient Thermal Measurement Part 2

“Heating time must be long enough to reach the thermal static equilibrium.” This is a basic rule for transient thermal measurement of semiconductor devices. However, there are some situations when it is difficult to follow the rule. In our previous paper, we found the valid data shown in the structure function will be limited to the area closer to the junction when unsaturated heating time is used. If the heating time is long enough to analyze the area in focus, unsaturated heating time can be used to shorten the measurement lead time. In the previous paper, ideal constant square heating pulses were assumed. This paper discusses the effect on power step variation due to the voltage change during the heating process. Five different heating pulses are compared to see their effects. Also, the adaptation of averaged power as the input for rectifying structure functions is also tested and confirmed that the idea is not suitable for generating structure functions.