Thermal analysis for observing conductive filaments in amorphous InGaZnO thin film resistive switching memory

Local heat produced by an electrical path inside the memory was detected and imaged by the method “Thermal Analysis.” It turned out that the visualized heat spots were conductive filaments (CFs) formed between interlayers of Pt/amorphous InGaZnO (a-IGZO). By using the thermal analysis, the location of CFs and their surface temperature was detected. This method indicated that there was a lot of emitted heat when the memory cell was switched off. It is thought to be accumulated heat causing disruption of the CFs. With great range of measurement, it was found that some memory cells drive with a single CF and others drive with multiple CFs. For the formation of CFs, it is assumed that there are CFs formation sites such as oxygen-related defects, roughness of the layer of a-IGZO, and so on. This method “Thermal analysis” can contribute to detection of the CF's location, the number of CFs, and thermal activity inside the memory devices.