Vishay SS26 Surface Mount Schottky Barrier Rectifiers

Gideon Analytical Laboratories received four Vishay SS26 Surface Mount Schottky Barrier Rectifiers for possible premature conditions to failure. A Schottky barrier is a potential energy barrier for electrons formed at a metal-semiconductor junction. Schottky barriers have rectifying characteristics, suitable for use as a diode. These Vishay SS26 Surface Mount Schottky Barrier Rectifiers feature a low profile package, high surge capability, and are RoHS compliant. The diodes came from PCB P/N 170310142001 Rev A03 S/N 051208-231. Positions D8, D9, D18, and D27 were identified as possible trouble spots. The goal was to determine the cause of failure.

Gideon Analytical Laboratories performed failure analysis on the  Vishay SS26 Surface Mount Schottky Barrier Rectifiers. There was no sign of external damage on any of the diodes. All four diodes were X-rayed, decapsulated, curve traced,  and analyzed by SEM-EDS. D8 showed considerable voiding in the solder to lead frame attachments. The failure site on D8 appeared to be the result of an over voltage spike which expelled the tin/silver solder on to the silicon dioxide glass insulator. A curve trace of D9 revealed a dead short. After removing the lead frame on D9, the failure site and step coverage damage were identified.  X-rays of D18 showed solder voiding. On D27, the solder puddle did not touch the silicon passivation and no step damage occurred. In conclusion, these Vishay SS26 Surface Mount Schottky Barrier Rectifiers were failing due to external factors.

Gideon Analytical Laboratories had been solving electrical problems for decades. You want your products to be reliable. You don’t want have anxiety about the uncertainty of if and when your products will fail. You want confidence in your products. Gideon Analytical Laboratories can give you that confidence. We have the experience, knowledge, and analytical equipment to get the job done correctly. If your company is having electrical problems with the design, manufacturing, or in the application, Gideon Analytical Laboratories can help.

D9 decapsulated, shorted die

D9 decapsulated, shorted die

D9 Failure site, voltage spike

D9 Failure site, voltage spike

D18 solder removed, no anomalies

D18 solder removed, no anomalies

X-ray D8, solder voiding

X-ray D8, solder voiding

X-ray D8, anode and cathode

X-ray D8, anode and cathode

D8 after decapsulation

D8 after decapsulation

D8, disturbance in step coverage

D8, disturbance in step coverage

D9, damage to step is visible

D9, damage to step is visible

D9 lead frame removed, failure site in red circle

D9 lead frame removed, failure site in red circle