Temperature Variation of DC Characteristics in Neutron-Irradiated Transistors.
Final technical rept. 18 May 70-30 Jun 71,
ALABAMA UNIV UNIVERSITY BUREAU OF ENGINEERING RESEARCH
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The purpose of the report is to describe simple techniques which have been developed for predicting the dc behavior of bipolar transistors which have been irradiated with fast neutrons. Equations were developed for the currents measured at the terminals of the transistor active region of operation in terms of junction bias voltage, current injection level, operating temperature, and fast neutron fluence neutronssq cm. Terminal currents are modeled as consisting of internal current components, each of which is associated with either a recombination process or a current injection across the emitter-base junction. Low injection effects are considered first, and then high injection effects are shown to follow from modification of certain terms in the equations. Lattice damage is shown to appear mainly in the form of carrier lifetime degradation. As a primary goal and a check on the veracity of the equations developed, the current gain, h sub FE, of a number of transistor samples was predicted from pretest data and compared with experimantal results. A number of extra electrical parameters were monitored as a cross-check of the model assumed. A double diffused structure with approximately exponentially-graded base was chosen for a number of calculations made for verification of the model, but only the emitter-base junction profile is crucial to the current-component technique if certain parameters are measured directly. Author
- Electrical and Electronic Equipment
- Radioactivity, Radioactive Wastes and Fission Products