# Diode Failure Analysis


A diode allows current to flow in one direction and blocks it in the other. Diodes are used for rectification, signal switching, voltage clamping and protection. The main types are signal, rectifier, Schottky, Zener and light-emitting diodes (LEDs).

Diodes fail in a few common ways. Electrical overstress (EOS) can melt metal or damage the junction. Mechanical stress can crack the die or the glass body, which causes an open circuit, an intermittent connection or a leakage path. Moisture or contamination can raise leakage current, and a poor solder or die-attach bond can open the circuit at high temperature.

The case studies in this category include a glass-sealed diode in a display socket that cracked from lead stress. Others include a signal diode with EOS damage to its epoxy body and silicon rectifier diodes that opened at high temperature.

The lab usually begins with curve tracing to find the electrical failure mode. We then decapsulate or open the part and inspect the die with optical microscopy. [Scanning electron microscopy](/analytical-services/scanning-electron-microscopy/) and [X-ray radiography](/analytical-services/x-ray-radiography/) help when more detail is needed.

If you have failed diodes, [request a quote](/contact/) and send us a description of the failure.


## Pages

- [Failure Analysis on 1N645 Silicon Rectifier Diodes](https://gideonlabs.com/posts/failure-analysis-on-1n645-silicon-rectifier-diodes/index.md)
- [On Semiconductor SS16 Schottky Rectifier](https://gideonlabs.com/posts/on-semiconductor-ss16-schottky-rectifier/index.md)
- [Failure Analysis on LUMEX SSL-LX093UWC/Gc LEDs](https://gideonlabs.com/posts/failure-analysis-on-lumex-ssl-lx093uwc-gc-leds/index.md)
- [Vishay SS26 Surface Mount Schottky Barrier Rectifiers](https://gideonlabs.com/posts/vishay-ss26-surface-mount-shottky-barrier-rectifiers/index.md)
- [Vishay SS26 Schottky Rectifier](https://gideonlabs.com/posts/vishay-ss26-schottky-rectifier/index.md)
- [MH Ballast Black Box PCB](https://gideonlabs.com/posts/mh-ballast-black-box-pcb/index.md)
- [Fairchild Transient Voltage Suppressor SMBJ5VOCA](https://gideonlabs.com/posts/fairchild-transient-voltage-suppressor-smbj5voca/index.md)
- [IR AUIRF7648M2 Power MOSFET](https://gideonlabs.com/posts/ir-auirf7648m2-power-mosfet/index.md)
- [Vishay ES2D SM Rectifier](https://gideonlabs.com/posts/vishay-es2d-sm-rectifier/index.md)
- [Rectifier Assembly Rotors](https://gideonlabs.com/posts/rectifier-assembly-rotors/index.md)
- [JanTXV1N821 Diode](https://gideonlabs.com/posts/jantxv1n821-diode/index.md)
- [Failure Analysis on JanTX1N649-1 Diodes](https://gideonlabs.com/posts/failure-analysis-jantx1n649-1-diodes/index.md)
- [Microsemi DZ771215A diode](https://gideonlabs.com/posts/microsemi-dz771215a-diode/index.md)
- [Potential Contamination Photodiode](https://gideonlabs.com/posts/potential-conamination-photodiode/index.md)
- [Integrated Switches and Signal Diodes](https://gideonlabs.com/posts/integrated-switches-and-signal-diodes/index.md)
- [Moisture Ingress Test](https://gideonlabs.com/posts/moisture-ingress-test/index.md)
- [FTIR of LEDs](https://gideonlabs.com/posts/ftir-of-leds/index.md)
- [Vertical Cavity Surface Emitting Laser](https://gideonlabs.com/posts/vertical-cavity-surface-emitting-laser/index.md)
- [MOC101 Photocoupler](https://gideonlabs.com/posts/moc101-photocoupler/index.md)
- [Varactor Diode GVD30601-001](https://gideonlabs.com/posts/varactor-diode-gvd30601-001/index.md)
- [Failure Analysis on 1N5626GP Diode](https://gideonlabs.com/posts/failure-analysis-on-diode/index.md)
- [Photocoupler Vishay IL420 Failure Analysis](https://gideonlabs.com/posts/photocoupler-failure-analysis-2/index.md)
- [Optocoupler Fairchild QTC H11N1 Failure Analysis](https://gideonlabs.com/posts/optocoupler-failure-analysis/index.md)
- [VCSEL Diode Failure Analysis](https://gideonlabs.com/posts/diode-failure-analysis-2/index.md)
- [Cracked Glass Diode in a Display Socket: Failure Analysis](https://gideonlabs.com/posts/diode-failure-analysis/index.md)
- [EOS of Signal Diode](https://gideonlabs.com/posts/eos-of-signal-diode/index.md)
- [BZT52B5V6-V Diode Failures](https://gideonlabs.com/posts/diode-failures/index.md)
- [Optocoupler Failures](https://gideonlabs.com/posts/optocoupler-failures/index.md)
- [Poor Process Control Lead to Over Current Failure](https://gideonlabs.com/posts/poor-process-control-lead-to-this-over-current-failure/index.md)
- [1N4148 Glass Diode Failures](https://gideonlabs.com/posts/glass-diode-failures/index.md)