Radiation resistant integrated circuit design

Abstract

Annular transistors are positioned with respect to the n-well diffusion region so that the active channels of the transistors are completely within the diffusion region, thereby avoiding the formation of the edges at the boundary between n active channel regions and adjacent field oxide region (the bird's beak region), which are susceptible to the effect of the ionizing radiation. The edgeless design of the gate arrays reduces the degradation of the transistors caused by the bird's beak leakage, while allowing for an unmodified commercial process flow for fabrication. An outer annular transistor and one or more inner annular transistors may be provided. The outer transistor may be used as an active transistor in the formation of logic circuits, or may provide isolation for the one or more inner transistors, which may be connected to form logic circuits. The design preferably includes a provision for readily disabling the radiation resistant system so the same design can be easily transformed into a non-radiation resistant design. Other electrical components such as a resistor may be formed with another annular gate electrode to isolate the component from the deleterious effects of ionizing radiation, as well.