Conductivity Modulation Effects in Diffused Resistors at Very High Dose Rate Levels

Integrated circuits are susceptible to burnout at extremely high dose rate levels. Several IC technologies utilize diffused resistors which are subject to conductivity modulation. These resistors, in some cases, may not provide sufficient current limiting at high dose rate levels to preclude burnout. One solution to this problem is to utilize thin film or thick film resistors, eg, Nichrome, to provide current limiting. Another solution is to use diffused resistors in dielectrically isolated tubs. To facilitate this solution, engineering expressions which accurately define conductivity modulation must be developed, and the current limiting which results must be adequately estimated. The problem has been previously addressed (ref 1); this paper extends the treatment by considering band-to-band recombination which is the most important basic effect limiting conductivity modulation at high dose rate levels.