Resistive switching in lateral junctions with nanometer separated electrodes

Resistive switching in lateral tunnel junctions is reported. Nanogap tunnel junctions made of Au/SiO2/Au and Au/TiO2/Au were patterned by electrical-beam-lithography (EBL) and a controlled electromigration process. Depending on the substrate material, different reproducible resistive switching characteristics were observed under vacuum conditions. While for TiO2 substrates bipolar resistive switching was observed, nanogap junctions on SiO2 substrates showed resistive switching characteristics with a negative differential resistance. The role of the substrate material with respect to the resistive switching behavior is discussed in the framework of the electrical breakdown. All experiments were performed under vacuum to suppress parasitic effects due to charged particles in ambient air. Nanogap resistive switching devices are promising candidates for densely integrated memresistive systems such as non-volatile resistive random memories (RRAMs), field programmable arrays (FPGAs), or artificial neural networks (ANNs).