Top-side pulsed laser induced single event upsets in highly-scaled SRAM devices

A pulsed laser system has been used to induce single event upsets (SEU) in highly-scaled SRAM devices. The events are induced from the circuit topside in areas where the higher metal layers have been eliminated by design from the circuit layout. The presence of metal tracks for voltage biasing, bit-line and word-line routing, difficult carrying out measurements to obtain the minimum energy required to induce an SEU. Off-chip transient currents caused by laser pulses have been measured; data indicates that most of such current is due to photocurrents generated in the well-substrate diode.