The effects of ionizing radiation on diffused resistors

A theoretical examination of the effects of ionizing radiation on diffused resistors performed to ascertain the feasibility of their use in hardened dielectrically isolated integrated circuits is described. The two basic effects — conductivity modulation, which is generally insignificant or can easily be rendered so, and photocurrent generation, the consequences of which essentially determine the diffused resistor hardness — are studied. Results indicate that typical dielectrically isolated diffused resistors are quite invulnerable to ionizing radiation. Design guidelines to achieve optimum hardness are implied. Initial findings of radiation experiments performed on a diffused resistor test chip are reported. When transient leakage dissociated with the resistor structures is accounted for, the results substantiate the primary conclusions of the theoretical study.