Modes of Avalanche Diodes and Their Associated Circuits

This paper attempts to put in perspective the modes of operation of avalanche diodes. Although theoretical treatments exist that encompass all known aspects of avalanche diode behavior, the compartmentalization of behavior into well-understood special cases is of enormous help to the device and circuit designer in understanding the peculiarities encountered in experimental work. The degree of compartmentalization is, of course, an arbitrary choice but the distinction of five modes seems appropriate. These are, respectively, the IMPATT, TRAPATT, and parametric modes, which are potentially useful, and the space-charge feedback and thermal modes, which probably are not. The latter two are important, however, in that they constitute a means of diode self-destruction. The presentation is tutorial and will hopefully remove some of the confusion introduced by the varied names employed by workers in the field to describe basically simular results. The approach is one of reason rather than legalism, and should this particular compartmentalization stand the test of time, appropriate nomenclature will no doubt be decided by an international committee.