Influence of the series resistance of on-chip power supply buses on internal device failure after ESD stress [MOS devices]

Bus wires of on-chip power supplies are resistive because of their limited width. During an ESD event, this resistance initiates a local internal overvoltage through a high discharge current peak, which can cause damage to internal source/drain areas. A detailed description of the mechanism that causes this internal damage and a simple estimation of the minimum width of power supply buses on semiconductor devices is given. Additional protection circuits for improving the ESD resistivity against internal failure are presented