Extended Single-Sided Row Hammer in DRAM: Concept and Physical Mechanism Analysis

초록

An extended single-sided row hammer (ESH) attack-a novel variant of the row hammer vulnerability-is proposed for the first time in 10 nm-class dynamic random-access memory (DRAM). This method enhances the single-sided row hammer (SH) technique by utilizing a transfer line to induce bit flips in memory cells that are not directly adjacent to the aggressor row. Unlike the double-sided row hammer (DH), which applies repeated pulses to both neighboring word lines of a victim row, the proposed ESH mechanism can induce bit flips with relatively fewer pulses on an adjacent word line, thereby disturbing cells beyond the immediate neighbors. Furthermore, the influence of interface trap density ( D-it) at the silicon fin-trench oxide interface is investigated as a key factor affecting the severity of ESH attacks. Simulation results demonstrate that a higher D-it intensifies the lateral electric field and increases electron current density, thereby accelerating charge loss in the memory node. 3D TCAD simulations confirm that these amplified electrical effects exacerbate ESH-induced bit flips. These findings underscore the necessity for novel refresh schemes capable of addressing indirect disturbance mechanisms in DRAM systems.

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