Gamma radiation effects on integrated injection logic cells

Integrated injection-logic (I²L) cells were tested to determine their characteristics after exposure to a total dose gamma-radiation environment. These particular devices were not designed or fabricated with radiation hardness as a goal. The common-base current gain of the lateral p-n-p transistor, the common-emitter current gain of the vertical n-p-n transistor and the forward current-voltage characteristics of the injector-substrate junction were measured over the current range of 100 nA to 300 µA as a function of dose. In addition, the propagation delay time versus power dissipation per gate at various dose levels was determined from frequency of oscillation measurements of a multiple inverter circuit.