Unexpected failure in power-rail ESD clamp circuits of CMOS integrated circuits in microelectronics systems during electrical fast transient (EFT) test and the re-design solution

Four different on-chip power-rail electrostatic discharge (ESD) clamp circuits have been designed to investigate their susceptibility to electrical fast transient (EFT) test. From the experimental results, the feedback loop in two kinds of on-chip power-rail ESD clamp circuits provides the lock function to perform a latchup-like failure after the EFT test. The re-design solution will be developed to overcome this issue to meet the regulation of EFT/EMC test.