Electro-thermal simulations of a PIN-diode based on the finite-element method, show a non-uniform temperature distribution inside the device during switching transients. Hence, the implicit assumption of a uniform temperature distribution when coupling an analytical electrical model and a thermal model yields inaccurate electro-thermal behaviour of the PIN-diode so far. The idea of including non-uniform temperature distribution into power semiconductor device models is not new, as accurate electro-thermal simulations are required for designing compact power electronic systems (as IC or MCM). Instead of using a one-dimensional finite difference or element method, the bond graphs and the hydrodynamic method are utilized to build an electro-thermal model of the PIN-diode. The results obtained by this original technique are compared with those obtained by a commercial finite-element simulator. The results are similar but the computation effort of the proposed technique is a fraction of that required by finite-element simulators. Moreover, the proposed technique may be applied easily to other power semiconductor devices.