R&D: Controllable Coexistence of Threshold and Non-Volatile Crosspoint Memory for Highly Linear Synaptic Device Applications

Journal of Physics D: Applied Physics has published an article written by Parthasarathi Pal, Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, Tainan 701401, Taiwan, Amit Singh, Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan, and Yeong-Her Wang, Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, Tainan 701401, Taiwan.

Abstract: “A highly reliable and versatile resistive memory device that demonstrates threshold and non-volatile memory (NVM) switching behaviour depending on the compliance current (CC) modulation was utilised by doping a semiconducting (Si) material into a high-k (HfO_x) film with highly linear synaptic behaviour. The device shifted towards volatile switching at a CC less than 1 µA and exhibited NVM behaviour at a CC limit above 10 µA. A 3-bit/cell data storage capability on RESET voltage modulation was implemented for high-density memory application. The device exhibited excellent programming linearity of potentiation/depression responses up to 10 000 pulses compatible with fast pulse (100 ns) with good I_ON/I_OFF ratio (>10³), stable data retention capability (10⁵ s) at 85 °C and high WRITE endurance (∼10⁷ cycles) with a pulse width of 200 ns. The neuromorphic applications were successfully emulated through neural network simulations using the experimentally calibrated data of the Si-doped HfO_x resistive cross-point devices. Simulation results revealed a low nonlinearity of 0.03 with 98.08% pattern recognition accuracy. The estimated results revealed the potential of the device as a low-power selector and high-density NVM storage in large-scale crossbar array in future neuromorphic computing applications.“