Analysis of the total dose-induced coupling effect in the partially-depleted silicon-on-insulator NMOSFETs

To make the integrated circuits operate stably, safely and reliably in the space radiation environment, the discrete MOSFETs must be carefully designed. In this paper, the effects of ionizing radiation on 130 nm PDSOI I/O NMOSFETs are investigated. The radiation-induced trapped charge in the buried oxide will depleted the nearby neutral body. After a certain doses of radiation, the partially-depleted device can transform to a fully-depleted one and a radiation-induced coupling effect can be observed. It is characterized by a significant negative shift of the front-gate threshold voltage and the decrease of the front-gate subthreshold slope. These results are also verified by the TCAD simulations. Furthermore, a simple model is proposed to calculate the radiation-induced negative shift of the front-gate threshold voltage through coupling effect. The calculated values are consistent with the experimental data.