Susceptibility of Integrated Circuits to Electrostatic Discharge

The components that are considered fairly rugged can be damaged by electrostatic discharge (ESD). Bipolar transistors, the earliest of the solid state amplifiers, are not immune to ESD, though less susceptible. Devices manufactured using metal oxide semiconductor (MOS) technology can be easily damaged due to ESD but some of the newer high speed components can be ruined with as little as 3 volts. The integrated circuits (IC) are susceptible to ESD due to its small size and unavailability of larger area to dissipate the excess energy. The susceptibility of ICís can be determined by various ESD stress tests. The different ESD stress modes on an input or output pin which is Pin-to-VSS, Pin-to-VDD are used to test an IC. The IC after ESD stresses may undergo damage not only in the input/output circuits or devices, but also in the internal circuits. The effects of ESD on various logic gates belonging to both transistor-transistor logic (TTL) and Complementary MOS (CMOS) logic families have been studied. The comparison between TTL and CMOS logic gates reveal that CMOS devices are more susceptible to ESD than TTL devices.