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 and X-ray radiography help when more detail is needed.
If you have failed diodes, request a quote and send us a description of the failure.
Microsemi DZ771215A diode
Gideon Analytical Laboratories received a failed Microsemi DZ771215A 10 watt diode for failure analysis. Two working devices were provided …
March 31, 2014Potential Contamination Photodiode
Gideon Analytical Laboratories received several photodiodes to examine for possible contamination. A diode is a two-terminal electronic …
March 28, 2014Integrated Switches and Signal Diodes
Gideon Analytical Laboratories received several components for failure analysis: two Fairchild FDC6324L integrated load switches and two …
July 1, 2013Moisture Ingress Test
Gideon Analytical Laboratories received 10 parts each of Everlight and Nichia, respectively, LED components to on which to perform a …
May 8, 2013FTIR of LEDs
Gideon Analytical Laboratories received a Unity PLCC LED and was asked to perform FTIR analysis for the purpose of materials compatibility. …
April 24, 2013Vertical Cavity Surface Emitting Laser
Gideon Analytical Laboratories received several VCSELs (vertical cavity surface emitting laser" with diminished light capacity over time for …
April 1, 2013MOC101 Photocoupler
Gideon Analytical Laboratories received three failed Vishay MOC8101 isolating photocouplers for failure analysis. These photocouplers are …
March 31, 2013Varactor Diode GVD30601-001
Gideon Analytical Laboratories received several GVD30601-001 super hyperabrupt junction tuning varactor diodes with a latent failure …
March 31, 2013Failure Analysis on 1N5626GP Diode
Gideon Analytical Laboratories received one failed 1N5626GP diode and several good ones for comparison. According to a Wikipedia post, a p–n …
November 27, 2012Photocoupler Vishay IL420 Failure Analysis
Gideon Analytical Laboratories received one failed photocoupler, a Vishay IL 420, for failure analysis along with two virgins (unused) …
November 27, 2012Optocoupler Fairchild QTC H11N1 Failure Analysis
Gideon Analytical Laboratories received several Fairchild QTC H11N1s, a high-speed logic optocoupler, in 6-pin plastic DIPs. The devices …
November 23, 2012VCSEL Diode Failure Analysis
Gideon Analytical Laboratories received several VCSELs (vertical-cavity surface-emitting laser) with diminished light capacity were …
November 22, 2012
