The harm of static electricity to sensitive components
Electrostatic discharge (ESD) is a well-known electromagnetic compatibility problem, which can cause electronic equipment to malfunction and more seriously damage electronic equipment. When semiconductor devices are placed alone or packed into circuit modules, permanent damage to these devices may be caused even if no power is applied. Components that are sensitive to electrostatic discharge are called electrostatic discharge sensitive devices (ESDS).
If the voltage between two or more pins of a component exceeds the breakdown strength of the component's dielectric, damage to the component will result. This is the main cause of failure of MOS devices. The thinner the oxide layer, the greater the sensitivity of the component to electrostatic discharge. The fault usually manifests as a short circuit phenomenon that the component itself has a certain resistance to the power supply. For bipolar components, damage typically occurs in the metallized active semiconductor area separated by a thin oxide layer, thus creating a leaky path.
Another type of failure is caused when the temperature of the node exceeds the melting point of semiconductor silicon (1415°C). The energy of the ESD pulse can generate localized heating and hence failure of this mechanism. This failure occurs even if the voltage is lower than the breakdown voltage of the medium. A typical example is that the breakdown between the emitter and base of an NPN triode will drastically reduce the current gain.
Functional damage may not occur immediately after a device has been subjected to electrostatic discharge. These potentially damaged components are often referred to as "lame" and, once in use, exhibit greater susceptibility to subsequent electrostatic discharge or conductive transients.
It is very important to pay close attention to the damage that occurs to the components under the discharge voltage that is not detectable. The electrostatic discharge voltage felt by the human body is between 3000-5000V, however, the voltage when the component is damaged is only a few hundred volts.
The harmful effects of electrostatic discharge began to be recognized in the 1970s, due to the development of new technologies that made components more and more sensitive to damage from electrostatic discharge. The damage caused by electrostatic discharge can reach more than several million dollars every year. Therefore, many large-scale component and equipment manufacturers have introduced professional technology to reduce the accumulation of static electricity in the production environment, thus greatly improving the product qualification rate and reliability. Users also understand the importance of preventing electrostatic discharge damage based on their own experience. So we should also pay attention to this item when buying large household appliances. Pay attention to check the instruction manual and certificate of conformity. Otherwise, it will be a hidden danger to family members. When it rains and thunders. It is best to turn off the household appliances that can cut off the power supply. In order to prevent unnecessary trouble. Regardless of whether it is a household appliance, as long as it is a large machine related to calls, we must pay attention to this point.