John B. Smyth

Hardness Assurance Considerations for Long-Term Ionizing Radiation Effects on Bipolar Structures

The purpose of this work was to assess the theoretical understanding of long-term ionization effects in semiconductor bipolar devices in support of developing hardness assurance techniques. The principal effort was directed at studying transistor gain degradation mechanisms by use of models relating semiconductor physical and electrical parameters to surface properties. Ionizing radiation effects on surface properties were used to identify critical physical parameters for use in hardness assurance procedures. Model implications and predictions were then compared with existing data to evaluate their accuracy and usefulness as a hardness assurance tool.

Predicting ESD Related Reliability Effects

This paper addresses a recent case history at Hewlett-Packard, where the cumulative effect of ESD damage has been observed in actual field failures on an LSI CMOS device. The failure rate of an LSI device accounted for a majority of the assembly line scrap as well as the majority of field returns. It was found that the two measuring points track each other and the line scrap rate can predict the field return rate for this failure mode. It was also found that the failure rate was constant with time for given populations.

Parameter Sensitivities for Hardness Assurance Displacement Effects in Bipolar Transistors: Part II

A worst-case neutron hardness assurance approach is presented that can be implemented by both the manufacturer and user and is in excellent agreement with the-CRIC data over the normal operating range. The limitations of the technique (VCE(SAT) and severe crowding) are pointed out and suggestions are made on how to approach these limitations.