Extension of the SUNRED algorithm for electrothermal simulation and its application in failure analysis of large area (organic) semiconductor devices

The Finite Differences Method (FDM) based Successive Network Reduction (SUNRED) algorithm is a fast and accurate distributed electro-thermal simulation method for microelectronic applications. A presented new extension can handle the Seebeck and the Peltier-Thomson effects. Organic Light-Emitting Diodes (OLEDs) are thin-film multilayer devices based on organic molecules or polymers. These devices are not only used as displays but they appear in intelligent lighting applications. The article introduces temperature-dependent OLED luminance modeling based on measurements and application of the models in the SUNRED algorithm to gain luminance maps. Because of the operational degradation of the OLED, non-emissive “dark” spots can appear. Cause of these spots can be e.g. manufacturing problem, damage of the surface protection, etc. Electro-thermal and luminance simulation of this failure type is demonstrated and is compared with measured results. Non-uniform light emitting polymer layer thickness or high current flux can cause the thermal runaway of the device; these effects are presented by DC and transient simulations.