Design of CMOS Compatible, High-Speed, Highly-Stable Complementary Switching with Multilevel Operation in 3D Vertically Stacked Novel HfO2/Al2O3/TiOx (HAT) RRAM

Complementary resistive switching (CRS) is a suitable approach to minimize the sneak leakage paths through a large resistive random access memory (RRAM) array. Here, an effective CRS design with a HfO2/Al2O3/TiOx (HAT) trilayer structure integrated in a 3D vertically stacked RRAM array is reported. The design shows voltage-controlled resistive switching and CRS performance with multilevel operations. High-speed switching is observed with the HAT design. The device shows SET and the RESET transitions with speeds of -3.5 V@30 ns and +3.8 V@ 150 ns, respectively. As well as with the DC measurements, the CRS switching is achieved under AC switching dynamics measurement. Maintaining the same applied pulse polarity, the lower amplitude can switch the device to the SET and the higher amplitude can switch it to the RESET. A highly nonlinear (nonlinearity >10(2)) CRS is obtained at a high temperature of 150 degrees C. In the HAT devices, the origin of CRS is due to the anionic redistribution in HfO2 and TiOx layers, leaving Al2O3 as tunnel barrier. The achievements reported here indicate the applicability of the HAT design for future high-speed high-density applications.