Control of the set and reset voltage polarity in anti-series and anti-parallel resistive switching structures

摘要

In the attempt to control the polarity of the set and reset voltages in bipolar resistive switching capacitors, we have studied the switching properties of structures consisting of either two anti-series or two anti-parallel metal-insulator-metal capacitors. The capacitors were based on hafnium oxide, and W and TiN/Ti were used as bottom and top electrodes respectively. MIM capacitors showed bipolar resistive switching behavior, with very good repetitiveness and endurance properties. Both anti-series and anti-parallel structures showed again bipolar resistive switching behavior, being the polarity of the set and reset voltages controllable by applying higher biases. In the case of anti-series configuration, there is a stretch-out in the current-voltage characteristic because the bias is applied across two different devices. Changing the polarity is equivalent to the process of write and erase of complementary resistive switching devices in crossbar arrays. In the case of anti-parallel configuration, the resistance window between both resistivity states is reduced. The control of the switching polarity has also been observed when applying a small ac signal, and measuring the conductance of the structures.