Understanding rectifying and nonlinear bipolar resistive switching characteristics in Ni/SiN_x/p-Si memory devices

Two resistive memory devices were prepared with different doping concentrations in the silicon bottom electrodes to explore the self-rectifying and nonlinear resistive switching characteristics of Ni/SiN_x/p-Si devices. Due to the reduced current overshoot effect, using electroforming at a positive bias can produce bipolar-type resistive switching behavior. A higher self-rectification ratio in the Ni/SiN_x/p⁺-Si device is achieved than in the Ni/SiN_x/p⁺⁺-Si device. The asymmetric I-V characteristics can be explained by the Schottky barrier that suppresses the reverse current, and it is controllable by the size of the conducting path. A conducting path with a high resistance value in a low resistance state is beneficial for a high selection ratio. Moreover, by controlling the compliance current, we demonstrate an improved self-rectifying and selection ratio. The results of our experiment provide a possible way to improve the nonlinear characteristics without the need for a selector device in CMOS compatible cross-point array applications.