Self-heating experimental study of 600 V PT-IGBTs under low dissipation energies

Abstract

The time evolution of temperature gradient in the drift region (N−-epilayer) of unirradiated and proton irradiated punch-through type 600 V insulated gate bipolar transistors (IGBT) structures has been measured by using the internal IR-laser deflection technique. This technique is applied in the device drift region, since N−-epilayer is transparent for the working wavelength (1.3 μm). High spatial (35 μm) and time (below 1 μs) resolution is achieved. The experimental results are explained with numerical thermal 2D-simulation and afterwards, compared with a simplified thermal model adapted to low dissipation energies. Good agreement is obtained between the experimental results and the thermal behaviour predicted by the model. Temperature gradients as low as 0.5 mK μm−1 have been measured with the proposed equipment in 5.9×5.9 mm2 IGBT chips.