High-Voltage and High-Current I d –V ds Measurement Method for Power Transistors Improved by Reducing Self-Heating

In this letter, an improved measurement method for power transistors is proposed to obtain drain-current characteristics as a function of drain-source voltage ( ${I}_{\text {d}}$ – ${V}_{\text {ds}}$ ) in high-voltage and high-current (HVHC) ranges. A simple double pulse test (DPT) is utilized in our previous method. However, the self-heating of the device under test (DUT) is not ignorable in the range of high ${I}_{\text {d}}$ . The improved test circuit is equipped with an additional transistor connected in parallel to DUT in order to prevent the flow of a large current into DUT before the measurement. When a trench-gate type SiC MOSFET (Metal-Oxide-Semiconductor Field-Effect-Transistor) is used as a DUT, the power loss of the DUT decreases by about 80%. The transient thermal analysis shows that the die temperature rise is suppressed by up to 10 °C in about 200 A ranges. The newly obtained ${I}_{\text {d}}$ – ${V}_{\text {ds}}$ characteristics are utilized to model the SiC trench MOSFET. The device model reproduces the measured switching waveforms very accurately.