Total Ionizing Dose Effect on Multi-state HfOxbased RRAM Synaptic Array

Emerging non-volatile memories (eNVMs) have demonstrated satisfactory accuracy on various applications in deep learning. Characterized by high density and low leakage power consumption, resistive random-access memory (RRAM) becomes very attractive in synaptic devices for deep neural networks (DNNs). RRAM-based synaptic devices include both analog and discrete versions. Unlike analog RRAM synapses which suffer from non-linearity, discrete but multi-state RRAM synapses are better suited for neural network hardware implementation. In this paper, the multi-state operation in RRAM arrays has been proposed as a synaptic device for deep neural network inference. Four-state conductance has been achieved in HfOx-based RRAM synaptic arrays. The impact of total ionizing dose (TID) on the multi-state behavior of HfOx-based RRAM is investigated by irradiating a 1-transistor-1-resistor (1T1R) 64 kb array with CMOS peripheral decoding circuitry fabricated at the 90 nm technology node with Co-60 gamma rays (60Co γ-ray irradiation).