Research On Sensitive Characterization Of Radiation Degeneration Of Electornic Devices

The electronic devices working in space suffers from radiation effects of spaceparticles, which leads to attenuation of their performance and life time due to thedegeneration of materials of devices after radiation. When degeneration accumulates toa certain extent, it results in device failure ultimately. With the development ofsemiconductor technology, it has been found that failure probability of devices increasesbecause of the decrease of key parameters caused by devices becoming smaller andsmaller. Additionally, size reduction can generate some new effects that influencereliability of the devices indirectly. Therefore, it is necessary to explore a sensitivecharacterization for radiation degeneration and new effects in order to assess reliabilityof the devices.In this paper, the physical mechanism of radiation degeneration in electronicdevices, especially in MOS and bipolar devices, has been researched. Based on theresearch, a method of sensitive characterization about radiation damage has beendeveloped. Moreover, the new single event effect in ultra-deep sub-micron devices hasbeen researched, which mainly focuses on charge sharing, multiple bits upset as well ascorrection of the original charge collection model. The main innovations andcontributions of this paper are the following:(1) The parameter degeneration by radiation in bipolar devices has been analyzed.According to its physical mechanism, a model of noise characterization has been builtand verified. In the experiments, the change rate of noise parameters would reach2500%if the change rate of electrical parameters was approximate3%, which indicatesthat noise parameters are more sensitive than electrical parameters. Thus, noiseparameters can be used as sensitive characterization of radiation damage for bipolardevices.(2) A research on ionization radiation effect and displacement radiation effect inbipolar devices is given. The research indicates that the degeneration mechanismsgenerated by these two radiation effects are not identical. Consequently, they were differentiated through experiments. As a result, the reverse current of a p-n junctiondiode could characterize ionization radiation effect, while the voltage of a p-n junctiondiode could characterize displacement radiation effect efficiently. The model andexperimental results illustrate that the ionization radiation effect is dominated in thecase of low radiation dose. However, the displacement radiation effect becomes moresignificant when radiation dose increases.(3) A research on physical mechanism of radiation degeneration in MOS devices iscarried out. According to the research, a radiation degeneration model and a noisecharacterization model have been constructed and validated separately. The resultsindicate that the increasing number of oxide-trapped charge and interface-trappedcharge produce a saturation phenomenon at different radiation doses and the saturationphenomenon of interface-trapped charge appears at lower dose. Besides, noiseparameters are more sensitive than electrical parameters. Therefore, noise parameterscan be used as sensitive characterization of radiation degeneration for MOS devices.(4) The1/f noise properties of pre-radiation in MOS devices have been analyzed,which demonstrates1/f noise pre-radiation is able to characterize the latent defect inMOS devices efficiently. Based on this analysis, a model for latent defect of MOSdevices has been built and verified. The results show that the pre-radiation1/f noisepower spectral amplitude is direct proportional to post-radiation threshold voltage drift.Therefore, this model is effective to characterize the quantity and severity of latentdefect in MOS devices by using1/f noise parameters.(5) The new effect of a single particle in ultra-deep sub-micron MOS devices hasbeen analyzed. Meanwhile, a new mechanism named charge sharing and a new effectnamed multiple bits upset have been discovered. Then a new model has been set upsince the previous charge collection model cannot be used for ultra-deep sub-microndevices. Using the new model, a simulation was implemented on90nm MOS devicesin order to test the charge collection, and it was verified by Technology Computer AidedDesign(TCAD). As a result, compared with the previous model, new model had moreaccuracy results that was consistent with TCAD simulation results. (6) The physical mechanism of multiple bits upset of a single particle in ultra-deepsub-micron MOS devices has been researched. It indicates that quantity and proportionof multiple bits upset will increase because of charge sharing and scale shrinking ofdevices. In the simulation, a characterization model was established based on criticalcharge Qcrand collecting charge Qco. It turns out that multiple bits upset is affected byLinear Transfer Energy(LTE), location of incidence as well as angle of incidence.