FORWARD CURRENT-VOLTAGE AND SWITCHING CHARACTERISTICS OF P+-N-N+ (EPITAXIAL) DIODES

The forward-biased current-voltage and forward-to-reverse biased switching characteristics of p+-n-n+ epitaxial diodes are investigated. The manner in which the n-n+ junction affects the flow of injected minority carriers in the epitaxial region is characterized by a leakage parameter a. Experimentally, for diodes with epitaxial film widths much less than a diffusion length, a “box” profile accurately describes the injected minority carriers in the n region. The current is found to increase with increased epitaxial width at a fixed bias. A general switching expression for epitaxial diodes is presented and the validity of the expression is shown experimentally. The experimental values of a, determined independently from the current-voltage and switching characteristics, are in good agreement and show that the leakage of the high-low junction is dominated by the recombination of minority carriers in the n-n+ space-charge region. Copyright © 1969 by The Institute of Electrical and Electronics Engineers, Inc.