Radiation And Noise Study For Optocouplers Of Transistor Output

As the rapid developments of advanced technologies of space technology, nuclear technology and nuclear weapons, an increasing number of optoelectronic devices are required to operate properly in irradiation environment. Irradiation introduces defects of oxide charges, interface state charges and internal displacements into the devices, causing a degradation of the electrical parameters and resulting in the devices with a semi-permanent or permanent ineffectiveness. Therefore, to ensure the devices work well in the radiation environment, it is necessary to make researches and diagnosis on their irradiation damage mechanism, damage degree and anti-radiation ability.Radiation-anneal techniques for devices of radiation environment are presently used.The more important thing is that this method will induce some new latent defects in the devices under test,let alone this method is expensive,time-waste and destructive.Under such conditions, a simple, quick and completely non-destructive technology for Radiation-anneal and anti-radiation evaluation is urgently required.Optocouplers with advantages of small size, long life, non-contact, and strong anti-interference are widely used in aviation and aerospace fields. So,it's urgent need to research the invalidation mechanism and the anti-radiation evaluation method of optocouplers in radiation environment.Defects are introduced in optocouplers by radiation and the defects are extraordinary correlation with noise.So,It's feasible to study the radiation damage of optocouplers in virtue of noise theory of optocouplers.In this paper, the systematic study of the irradiation effects, damage mechanism and evaluation method of optocouplers with transistor output is presented. For the composition of the optocouplers with transistor output, the noise theory, radiation mechanism and radiation effect are expounded, establishing an irradiation noise test system. And described in detail is the irradiation properties of both the total ionizing dose and neutron fluence. By choosing 60COγas the radiation sources to make the total ionizing dose, established a current transfer ratio model and noise model for optocouplers under the irradiation of total dose for the first time. The neutron fluence irradiation is carried out on reactor to study electric and noise effects of optocouplers, and an analysis of the fractal characteristics of the neutron irradiation noise is given, which provides research ideas and data for the irradiation study of optocouplers. A method of using irradiation noise to characterize the related parameters is proposed, which fills in this field at home and abroad.Combining with the above theory, working principles of semiconductor devices and the noise evaluation method for the reliability of optocouplers, noise assessment methods for evaluating the anti-radiation capacity are researched, obtaining important research results which establish the experimental and theoretical basis for the further development of irradiation evaluation methods for semiconductor devices.