When there is a difference in electrostatic potential between two charged objects, an exchange of electrostatic energy occurs causing their potentials to become balanced. This exchange of energy is called an Electrostatic Discharge.

An Electrostatic Discharge occurs when there is friction or separation.

When there is a discharge, even at a low voltage below 200V, Gate Oxide destruction or Junction spiking failure may occur.

The level of electrostatic discharge that humans can normally feel is above 3000V~4000V. However, most semiconductors can be damaged by a discharge below levels we can feel.

The exchange of electrostatic energy between two charged objects is explained by the figure given below. According to their priority, one object loses an electron to become positively charged, and the other object gains an electron to become negatively charged.

The Human Body Model ESD is a modeling of a situation where a certain amount of energy from an external electrical power or an electrostatic energy source becomes charged within the human body to become discharged as electrostatic energy. The MIL-STD sets the Resistance as 1500 Ohm, and Capacitance as 100pF for testing. The basic test circuit can be configured as shown below.

The Machine Model is a modeling of a situation where electrostatic energy is charged within the machine through a grounding problem or some other negative influence. The basic test circuit for a Machine Model can be configured as shown below

The Charged Device Model is when an electric charge within the Package becomes discharged through an external conductive material, and the device is damaged through a self-discharge. This model is different from other electrostatic discharge models in that the Pulse duration is very short, which causes Oxide failures such as oxide or poly-filament breakdown.