Abstract
Single event effect (SEE) induced mutual interference in CMOS circuits, including single event (SE) induced coupling effects (crosstalk) and modulation in local supply voltage on power-supply rails, was studied based on the increase in metal interconnect density. The dependence of SE vulnerability on metal interconnects was experimentally investigated using heavy ions and pulsed laser. Numerical simulation was performed to evaluate the modulation in local supply voltage induced by SEEs. Two groups of test structures with various metal interconnects between well contacts and the first metal layer were designed and fabricated. All other parts, including well contacts in the active regions, are of the same structures. Experimental results show that the upset cross section decreases with an increase in metal interconnect contact (CT) density between the active region and the first metal layer, suggesting a dominant contribution of rail voltage drop induced by charge sharing rather than SE-induced crosstalk. The differences in upset cross sections with cells of different CT hole densities appear the most evident ones under low frequency and high linear energy transfer value conditions. When transient-induced upsets play a more important role, the differences get weakened due to masking effects.
Highlights
With the design and fabrication of integrated circuits entering the deep submicron- and nano-scale era, on the one hand, devices and interconnect wires are being placed at an ever-increasing proximity, resulting in enhancement in single event (SE)-induced coupling effects between the interconnecting wires
Since the power supply current was limited to 100 mA, a voltage drop of less than 0.1 V could occur in metal lines due to single event effects (SEEs)
The larger the transient current between N-well and P-well contacts is, the stronger the voltage drop through the power supply buses will be
Summary
With the design and fabrication of integrated circuits entering the deep submicron- and nano-scale era, on the one hand, devices and interconnect wires are being placed at an ever-increasing proximity, resulting in enhancement in single event (SE)-induced coupling effects (crosstalk) between the interconnecting wires. On the other hand, the possibility of single ion induced charge sharing in a comparatively large region increases noticeably. Referring to Ref. 7, large latch-up currents induce significant voltage drops in Vdd and Vss rails, resulting in latch-up spreading. Referring to Ref. 7, large latch-up currents induce significant voltage drops in Vdd and Vss rails, resulting in latch-up spreading. Since the power supply current was limited to 100 mA, a voltage drop of less than 0.1 V could occur in metal lines due to single event effects (SEEs). Several other works studied radiation-induced rail voltage drop as well through irradiation experiment and simulation. Referring to Ref. 8, SEE-induced rail voltage drop is likely to happen when the disturbance spreads to a comparatively large region. The dependence of SE vulnerability on metal interconnects was experimentally investigated using heavy ions and pulsed laser, and numerical simulation was performed to evaluate the modulation in local supply voltage induced by SEEs. Two groups of test structures with various metal interconnects between well contacts and the first metal layer were designed and fabricated. Our paper aims to give a quantitative insight into the mutual interference related to metal interconnects
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