Research On Radiation-Damage-Noise Test Structures Of SiO₂ Dielectric Material

Silicon dioxide(SiO2) is afamiliar kind of dielectricmaterials in integrate circuits(IC), and also is the part which is the most liable toradiation damage in MOS devicesand IC. Therefore, the research on radiation effect of SiO2 dielectric material wouldensure the reliability of MOS devices and IC, which are used in the nuclear radiationenvironment. The noise is nearly interrelated with the inner defects in the materials anddevices, and could be used as a nondestructive evaluation tool. Moreover, SiO2 isinsulated material. For the research on radiation-resistant capability of SiO2 dielectricmaterial, a kind of sample structures, which could be sensitive to reflect its radiationdamage and easy to measure its representation parameters,must be design.In this paper, for designing the radiation-damage-noise test structures of SiO2dielectric material and using low-frequency 1/f noise to describe its radiation-resistantcapability,theprimarycontributions andconclusionsareshownasfollows:1. Radiation effect and noise mechanism of SiO2 dielectric material have beenstudied deeply, and radiation damage model and 1/f noise model of SiO2 dielectric inMOSFET have been established. Through the researchon microcosmic information ofthe latent defects in the models, MOSFET radiation degradation model which based onpre-irradiation 1/f noise has been established and the forecast technique of radiation-resistant capability on MOSFET has been proposed. Namely, through the measurementof pre-irradiation 1/f noise in MOSFET, threshold voltage drifts due to oxide-trap andinterface-trap charge after some dose radiation could be predicted. The simulationresults of the model agree well with the measurement results that proves the validityofthemodel.2. Based on the theory model, which is the quantitative mathematic model ofMOSFET radiation degradation and noise description, of SiO2 dielectric material teststructure design, general design criterion of the test structureshas been established, andthe physical structure, the layout structure and the manufacture designs of the testsamples havebeenaccomplished.