A PRODUCT ENGINEERING MEASURE FOR THE IMPROVEMENT OF PRODUCTION TECHNIQUES TO INCREASE THE RELIABILITY AND TO IMPROVE PRODUCT CAPABILITY OF HIGH VOLTAGE MINIATURE SILICON RECTIFIERS.
Final progress rept., 30 Dec 64-30 Jun 66,
GENERAL ELECTRIC CO AUBURN N Y SEMICONDUCTOR PRODUCTS DEPT
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Experimental results support the hypothesis that reduction in peak surface field will result in improved life test survival. A pellet design was chosen based on the required surface field. Theoretical calculations were made to determine the bevel angle for this design. Improved performance during reverse recovery has been obtained by using N-type silicon to permit gradual decay in reverse recovery current. A model for the origin of snapback failure has been proposed. A new technique for glass encapsulation was developed, which has lowered reverse leakage currents and in combination with a new etching technique has improved the device reliability. A new slug - lead was designed and tested which exhibits improved thermal resistance and lead fatigue over the original design. Several pieces of production equipment were designed and proven operational, based on the improvements made in the subject rectifier. The improved device has met the reliability objectives of the contract. The comparison of the new A14 device with the original A13 device shows a 50 to 1 failure rate improvement at 92C. junction temperature at 90 Confidence. The Environmental and Reliability Specification was approved and the improved rectifier has been tested to the various conditions and limits with good results. Test sequencing as required for acceptance produced some unexpected failures in lead fatigue and surge. Author
- Electrical and Electronic Equipment
- Ceramics, Refractories and Glass