Activation Energies of Thermal Annealing of Radiation-Induced Damage in n- and p-channels of CMOS Integrated Circuits, Part II

In Part I of this work, tempering and isothermal curves of annealing of radiation damage in p- and n-channels of RCA CD4007A CMOS integrated circuits were obtained for both the commercial ("soft") and J-process (106 rad-hard) fabrication technologies. These experimental data were analyzed for activation energies of thermal annealing using two independent theoretical treatments. Analysis of the activation energy distributions obtained indicated that the radiation-induced charge trapping in the gate oxide occurs mainly around the impurity centers. In this work, the same procedures are applied to devices of RCA's Z-process (105 rad-hard). Thermal annealing investigation of the Z-process reveals an anomalous annealing behavior of the p-channels, as compared to the p-channels of the commercial and J-processes. The thermal annealing-induced shift of the threshold potential extends far below the original value, which necessitated the development of a new mathematical treatment. This new treatment is presented here.