Failure of electronic components facts for kids

Failed chip in a laptop. Wrong power connection caused it to get super hot and melt its plastic case.

Electronic parts, like those in your phone or computer, can stop working for many reasons. These problems are called failure modes. They can happen because of too much heat, too much electricity, or even physical damage. Sometimes, the outer case of a part can break, letting in dirt or moisture, which then damages the inside.

Most electronic parts tend to fail either very early in their life or much later, near the end. This pattern looks like a "bathtub curve" on a graph. To catch early failures, companies often "burn-in" new parts by running them for a while. This helps find any weak parts before they are sold. It's super important for things like airplanes, medical devices, and phones to have reliable parts.

If a part suddenly breaks and stops working (a "fail-open" fault), it can cause other parts to break too. For example, if a wire on a chip breaks, it can create a huge power surge that damages other parts. Also, if a part gets too hot and keeps getting hotter (called thermal runaway), it can melt, catch fire, or even explode!

Why Electronic Packaging Fails

The outer casing, or packaging, of an electronic part is like its protective skin. Most electronic failures happen because of problems with this packaging.

How Temperature and Moisture Hurt Packaging

Heat changes: When materials heat up and cool down, they expand and shrink. If different parts of the packaging expand at different rates, it creates stress. This stress can cause tiny cracks over time, like when you bend a paperclip back and forth until it breaks.
Humidity and chemicals: Water and harsh chemicals can cause the packaging and its connections to rust or break down. This can damage the inside parts and stop them from working.
Too hot: If a part gets much hotter than it's designed for, the tiny wires inside can tear loose. The chip itself might crack, or the plastic case could break open.
Cracks: Humidity, sudden heating, or even dropping the part can cause cracks in the packaging.

Problems Inside the Package

Broken wires: During manufacturing, the tiny wires that connect the chip to the outside pins can break, get tangled, or touch the chip where they shouldn't.
Cracked chips: The main chip inside can crack from too much stress or sudden temperature changes.
Dirty parts: Tiny bits of metal or other materials can get stuck inside the package. These can cause short circuits, especially if they move around when the device is shaken.
Chemicals inside: Sometimes, unwanted gases or chemicals get trapped inside the package during manufacturing. These can also come from the materials used in the package itself, especially if they get too hot. These chemicals can cause corrosion and damage over time.
Leaks: To check for leaks, manufacturers sometimes put a special gas like helium inside the package. If the gas leaks out, they know there's a problem.
Poor heat transfer: If the chip isn't properly attached to its base, air pockets can form. These pockets stop heat from escaping, making the chip get too hot and fail.

Silver Migration and Shorts

Some materials in packaging, like a flame retardant called red phosphorus, can cause problems if not properly coated. If moisture gets in, it can turn into an acid. This acid, along with electricity, can make tiny bits of silver move and create a bridge between two nearby pins. This causes a short circuit. If you heat the part, the bridge might break, and the short disappears, only to come back when it cools down.

Contact Failures

Electrical contacts are where two parts touch to let electricity flow.

Resistance: Even good contacts have a tiny bit of resistance. If the contact isn't strong enough, or if there's dirt or rust, this resistance can go up a lot. High resistance makes the contact heat up, which can cause the circuit to fail.
Solder problems: The solder joints that connect parts to a circuit board can also fail. They can break down over time, especially if the part and the board expand differently with heat. This can cause tiny cracks in the solder.
Loose particles: Tiny bits of metal or dirt can get inside the device and cause short circuits, especially when the device is moved or shaken.
Rust: Rust and other non-conductive stuff can build up on contacts, making them unable to carry electricity properly.
Tin whiskers: Sometimes, tiny metal "whiskers" can grow from tin-coated parts. These whiskers can cause short circuits inside the package.
Cables: Wires and cables can also break from bending too much, fraying, or getting damaged by fire.

Printed Circuit Board Failures

Bad rust on a circuit board from a leaking battery.

Printed circuit boards (PCBs) are the green or brown boards with all the lines and dots. They are also sensitive to their environment.

Corrosion: The metal lines (traces) on the PCB can rust. Sometimes, they are not etched correctly during manufacturing, leaving tiny shorts.
Cracks: The traces can crack if the board is bent or stressed, making the circuit unreliable.
Leftover chemicals: Residues from the soldering process or other materials can cause electrical leaks or corrosion. Some chemicals can even attract moisture, creating a thin layer of water that conducts electricity between the traces.
Delamination: The layers of a multi-layer PCB can separate. This can crack the connections between layers and let in dirt or moisture, causing more problems.
Conductive filaments: Tiny metal "filaments" can grow inside the board, especially if there are small damages or poor connections. These filaments can cause current to leak or even short circuits between the traces.

Relay Failures

A relay is an electrical switch that opens and closes contacts.

Contact wear: Every time a relay opens or closes, a tiny spark (an "electric arc") happens between the contacts. This arc wears down the metal contacts, like tiny bits of welding.
Damage: The heat and current from these sparks create small craters and bumps on the contacts. Also, carbon and other materials can build up.
Short life: This damage greatly reduces how long a relay can work. A relay might last for millions of mechanical operations, but only about 100,000 electrical operations because of this contact wear.

Semiconductor Failures

Semiconductors are the tiny chips that make up most electronic devices. Many failures in these chips create "hot electrons," which can be seen with special cameras. This helps engineers find where the problem is.

Crystal and Oxide Problems

Crystal defects: Tiny flaws in the chip's crystal structure can grow, especially with heat or high current. This can make the chip work less well or stop it completely.
Trapped charges: In some chips, like those used for memory (EEPROM), electrical charges can get stuck in the insulating layers. This changes how the chip works and limits how many times you can save or erase data.
Corrosion: If the protective layers on the chip aren't perfect, moisture can get in and cause the metal parts to rust. This is a common cause of failures that show up later.

Parameter Failures

Bad connections: Tiny connections on chips, called vias, can have too much resistance. This slows down the chip. If the resistance drops when the chip gets hotter, it can be a sign of this problem.
Narrow spots: Sometimes, the metal lines on a chip are too narrow in places (called "mousebites"). These spots might not cause problems during testing, but they can be weak points that fail later, especially with high current.
Hidden delays: Sometimes, different parts of a circuit might be slightly off, but still within acceptable limits. However, when combined, these small differences can cause signals to slow down too much. This might only happen under specific conditions, like high speed or low power, leading to strange behavior.

Metallisation Failures

Close-up picture of a failed power transistor due to a short circuit.

Metallisation refers to the tiny metal lines that connect different parts of a chip.

Electromigration: This is when electricity pushes metal atoms out of place. It can cause the metal lines to get thinner or even break, increasing resistance or causing shorts to nearby parts. Adding a small amount of copper to aluminum lines can help prevent this.
Whiskers: Mechanical stress, high currents, or corrosive environments can cause tiny metal whiskers to grow, leading to shorts.
Silicon lumps: In some chips, silicon atoms in the metal lines can clump together when heated. These clumps act like empty spaces, increasing resistance and shortening the chip's life.
Bad contacts: The connection between the metal lines and the semiconductor material can degrade. This increases resistance and makes the chip work less efficiently.

Electrical Overstress (EOS)

Most chip failures related to stress are caused by too much heat in tiny spots. This can melt parts of the chip, change its structure, or speed up other failure processes.

Thermal runaway: If a small area on the chip gets hot, it can cause more heat to build up, leading to a runaway effect that damages the chip. This can happen if there are air pockets under the chip or from electromigration.
Wrong voltage: Some parts, like diodes, are designed to let current flow in one direction. If you apply voltage in the wrong direction (reverse bias), even a small amount can damage them immediately. For example, most LEDs can only handle about 5 volts in reverse.
Zener diode shorts: If a Zener diode gets too much reverse voltage, it can short circuit. The high current melts the inside, creating a permanent short. This is sometimes used on purpose to "blow" a fuse on a chip.
Latchups: If a chip gets a sudden surge of too much or too little voltage, a hidden "parasitic" circuit can turn on. This can cause a huge current to flow, damaging the chip. Latchups can be triggered by static electricity or even by other parts of the chip.

Electrostatic Discharge (ESD)

Electrostatic discharge (ESD) is a sudden burst of static electricity, like when you get a shock from touching a doorknob. It's a type of electrical overstress and can cause:

Immediate failure: The device stops working right away.
Parameter shifts: The device still works, but its performance changes permanently.
Hidden damage: The device seems fine, but it will fail much faster later on.

ESD causes damage through heat, high current, and strong electrical fields.

Oxide breakdown: The thin insulating layers (oxides) on chips can be broken by strong electric fields. This creates a path for current where there shouldn't be one.
Junction damage: The connections inside the chip can be damaged, causing current to leak or short.
Metal burnout: The metal lines on the chip can melt or vaporize, breaking the connection.
Charge injection: High-energy electrons can get stuck in the insulating layers, causing problems.

Catastrophic ESD failures (immediate and complete failure) are the most obvious but also the rarest. Parametric failures (performance changes) are more common, and latent failures (hidden damage that causes later failure) are the most common of all. For every parametric failure, there are many more latent ones.

Modern chips are more sensitive to ESD because their parts are smaller and their insulating layers are thinner. For example, the gate oxide of some transistors can be damaged by just 50 volts of static electricity. Even if it doesn't fail immediately, the damage can lead to a delayed failure after the chip has been used for a while.

Passive Element Failures

Passive elements are basic parts like resistors and capacitors.

Resistors

A resistor from a high voltage circuit damaged by arcing (electrical sparks).

Resistors control the flow of electricity. They can fail by:

Breaking open or shorting: They might stop conducting electricity (open) or conduct too much (short).
Value changes: Their resistance value can change due to manufacturing flaws or environmental conditions. For example, if the end caps on a resistor are loose, its value can become unstable.
Delamination: In small surface-mount resistors, the layers can separate, especially between the ceramic and the resistive material.
Corrosion: Some resistors can be damaged by chemicals, increasing their resistance.
Silver sulfide: Resistors with silver contacts can fail in environments with sulfur, as a non-conductive silver sulfide builds up.

Potentiometers and Trimmers

Potentiometers and trimmers are adjustable resistors, often used for volume control.

Wear and tear: The moving part (wiper) can wear down the resistive path, causing the resistance to change unevenly.
Dirt and moisture: These parts are often not perfectly sealed, so dirt, moisture, or even leftover solder chemicals can get inside and cause problems.
Physical damage: Bending or stressing the leads during installation can crack the internal parts, leading to failure.

Capacitors

Capacitors store electrical energy. They can fail by:

Dielectric breakdown: The insulating material (dielectric) between the capacitor's plates can break down if there's too much voltage or if it gets old. This can cause a short circuit. Some capacitors can "heal" themselves by vaporizing the damaged spot.
Material migration: The materials from the capacitor's plates can move across the dielectric, creating conductive paths.
Broken leads: The wires connecting the capacitor can break off due to rough handling, leading to an open circuit.
Contamination: Dirt or leftover chemicals can increase the capacitor's "dissipation factor," meaning it wastes more energy as heat.

Electrolytic Capacitors

Electrolytic capacitors are a common type of capacitor.

Drying out: Aluminum electrolytic capacitors contain a liquid electrolyte. This liquid can dry out over time, especially with heat. This causes the capacitor to lose its ability to store charge and increases its internal resistance. They often fail by shorting out.
Contamination: If the electrolyte gets contaminated (e.g., with moisture), it can corrode the internal parts, leading to shorts or loss of capacitance.
Gas buildup: Some electrolytes can produce gas, which builds up pressure inside the capacitor. This can cause the capacitor to bulge or even explode, a problem known as the capacitor plague.
Overstress: Tantalum capacitors can be permanently damaged by too much voltage, leading to shorts or open circuits.

Metal Oxide Varistors

Varistors protect circuits from sudden voltage spikes.

Thermal runaway: If a varistor's trigger voltage drops (meaning it turns on too easily), it can start to conduct too much current and get hotter and hotter. This can lead to a small explosion or fire. To prevent this, they are often used with a fuse that will blow if the varistor overheats.

MEMS Failures

Microelectromechanical systems (MEMS) are tiny machines built on chips, like accelerometers in your phone.

Sticking: Moving parts in MEMS can sometimes get stuck together (called stiction). A small shake might fix it.
Particles: Tiny dust particles can get into the system and block movements or cause shorts if they are conductive.
Breaks: The tiny mechanical parts can break.
Fatigue: Repeated movement can cause cracks in the moving structures over time.
Dielectric charging: Electrical charges can build up in insulating layers, changing how the MEMS device works.

Images for kids

Bad rust on a circuit board from a leaking battery.
Close-up picture of a failed power transistor due to a short circuit.
A resistor from a high voltage circuit damaged by arcing (electrical sparks).