Difference in Device Temperature Determination Using p-n-Junction Forward Voltage and Gate Threshold Voltage

Determination of chip temperature is a key element in the lifetime estimation of power devices. There are several temperature sensitive electrical parameters for this purpose, which allow accurate measuring of the chip temperature on fully packaged devices. Among all these parameters, the forward voltage of a p-n junction is probably the most widely used parameter for temperature determination of a power semiconductor device. In metal-oxide-semiconductor (MOS) gated power semiconductor devices, gate threshold voltage is an alternative parameter with high temperature resolution. In this paper, the p-n-junction forward voltage and the gate threshold voltage of MOS-gated power devices were investigated. The difference between temperature measurements via the two methods was analyzed.