sneakpath

Sneakpath refers to parasitic current paths that arise in high-density crossbar arrays of two-terminal resistive switching devices, such as memristors. In a crossbar, each intersection represents a memory element controlled by voltages applied to perpendicular word lines and bit lines. During read or write operations, voltages on unselected lines can create unintended pathways through neighboring, non-target devices, allowing current to sneak through multiple cells. This phenomenon can compromise read accuracy and increase power consumption, posing a major obstacle to scaling crossbar memories.

The mechanism depends on the nonlinearity and state of the devices in the array. If neighboring cells are in conducting states or the devices lack strong nonlinearity, sneak currents become more prevalent. Read margins shrink as the voltage divider formed by a network of programmed and unprogrammed cells reduces the distinguishability of the targeted cell’s resistance. Disturbances can also inadvertently alter the states of adjacent cells.

Mitigation strategies combine device, circuit, and architectural approaches. The most common solution is adding a selector device in series with each memory element (1T1R configuration) to suppress leakage. Nonlinear or threshold-type selectors, or the use of complementary resistive switching (CRS) architectures, also reduce sneak currents. Alternative approaches include bias schemes that apply half-select voltages (such as V/2 or V/3) and specialized readout protocols, as well as material engineering to increase device nonlinearity. These strategies aim to enable dense crossbar arrays with reliable operation for non-volatile memory and neuromorphic computing.