Damage thresholds of p-n junction devices by a current pulse method
First Claim
1. An improved method for determining the damage threshold of a semiconductor p-n junction comprising the steps of:
- applying a reverse polarity constant current pulse of less than 100 nanoseconds in duration to said p-n junction;
measuring elapsed time from the initial application of said constant current pulse to a point at which second breakdown occurs indicated by a significant drop in breakdown voltage;
calculating said damage threshold of said p-n junction from a time integral of said breakdown voltage over said elapsed time multiplied by said constant current level.
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Abstract
An improvement of the Wunsch test method for measuring pulsed-power failure thresholds of bipolar transistors and p-n junction diodes using short-pulse testing with pulse durations of 100 nanoseconds or less. A square pulse of reverse current is used to damage the p-n junction of interest, and the absorbed power is computed from oscilloscope traces of voltage and current. A constant-current pulse is used rather than the constant power pulse of the Wunsch test method, thereby limiting the damage done to the device and permitting a wide range of device parameter to be observed. The degree of device degradation is utilized to distinguish between true and false measurements of thresholddamage input-power and also to ensure that the individual failure levels of specimens of a sample actually are threshold failure levels rather than overkill levels, in order that the average of these levels represents, approximately, a 50% probability of failure for the sample. The current-pulse method simplifies the pulse-test procedures and produces damage threshold data which is many times more accurate than that which has been produced by previous methods.
3 Citations
8 Claims
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1. An improved method for determining the damage threshold of a semiconductor p-n junction comprising the steps of:
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applying a reverse polarity constant current pulse of less than 100 nanoseconds in duration to said p-n junction; measuring elapsed time from the initial application of said constant current pulse to a point at which second breakdown occurs indicated by a significant drop in breakdown voltage; calculating said damage threshold of said p-n junction from a time integral of said breakdown voltage over said elapsed time multiplied by said constant current level. - View Dependent Claims (2, 3, 5, 6, 7, 8)
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4. A method for determining the damage threshold in a semiconductor junction through second breakdown comprising the steps of;
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applying a constant current pulse to said semiconductor junction having a duration of less than 100 nanoseconds and sufficient magnitude to induce second breakdown within said duration of said pulse without causing catastrophic failure in said semiconductor junction; measuring the power absorbed by said semiconductor junction from a time integral of an average voltage level produced across said semiconductor junction multiplied by said constant current magnitude in response to the application of said constant current pulse measured over a time duration starting after an initial turn-on spike and ending at a point where second breakdown occurs indicated by a significant drop in said average voltage level.
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Specification