Investigation of the forming program failture in 1T1R structure

The programming successful ratio is an important aspect for the reliability of resistance random access memory (RRAM) array. During forming process, the gate bias should overcome not only the voltage potential aroused by source bias but also the increased threshold voltage (V´_Th) by body effect in one transistor and one resistor (1T1R) architecture. When the voltage drop on RRAM (V_RRAM) increases to a certain level (V_th+V_RRAM≈V_G), the transistor would be turned off and fail to switch the resistor to low-resistance-state (LRS). This result suggests that the forming voltage of the RRAM device should be controlled in a certain range in order to guarantee the successful forming program. The elucidation of failure mechanism of forming process is helpful to improve the yield of 1T1R array.