Study On Single-event Effect Of Low Dropout Regulator

With the rapid development of space science and technology,the integration of integrated circuits becomes more and more high.Various electronic components are widely used in spacecraft.Although the Earth and its adjacent environment have an atmosphere that blocks ultraviolet rays and cosmic rays,such conservation is limited in space.The complex space radiation environment will bring serious radiation safety problems to electronic components and their circuits.In order to study the effects of space radiation,the radiation environment is divided into radiation zones,cosmic rays,solar wind and solar flares.It is these radiation particles from different sources,such as electrons,protons and heavy ions,which are very easy to cause serious radiation safety problems for electronic components and circuits on spacecraft,such as aeronautics and spaceflight.In recent years,the research on the spatial radiation effects of semiconductor devices and their circuits and the improvement of their radiation resistance have become a very important topic in microelectronics both at home and abroad.As an important semiconductor device,power chip is widely used in space radiation fields such as satellite and spaceship.As one of the important components of various electronic equipment,its performance is directly related to the technical index of the whole electronic equipment and whether it can work reliably.Once the circuit of electronic components fails in the environment of space radiation,It will bring serious trouble to the whole spacecraft and satellite,and cause great economic loss.Therefore,it is very important to study the spatial radiation effect of power chip in depth.From the point of view of radiation damage mechanism,the two basic effects of radiation on semiconductor materials are ionization damage effect and displacement damage effect.In microcosmic terms,the ionizing damage effect is mainly caused by the interaction between irradiated particles and electrons in the target atom,which transfers its own energy to electrons,resulting in the electron obtaining more energy than its binding energy and leaving the nucleus to become free electrons.A hole-electron pair is formed.The effect of displacement damage is that the penetrating force of the irradiated particles is very strong enough to be close to the nucleus of the irradiated material,and the elastic collision between the irradiated particles and the atomic nucleus causes the lattice atom to obtain energy away from the original position.The gap position entering the lattice becomes a gap atom,and the original position becomes empty.That is to say,the defect of Frenkel was formed.No matter the ionization effect or the displacement effect,the electronic components and their circuits may bring a serious safety hazard in the practical application of the space environment.Therefore,from the point of view of reliability,the space radiation environment simulation experiment of the electronic components applied in the space environment should be carried out,and the space radiation conditions should be simulated by simulating the space radiation conditions.In order to reduce the failure and failure in the practical application,the performance index of the device in the space radiation environment is evaluated in order to reduce the fault and failure in the practical application.Improve its reliability and safety.In this thesis,the heavy ion single-particle experiment of low-pressure difference linear regulator(Low Dropout Regulator,LDO)was carried out by means of the HI-13 electrostatic tandem accelerator of China Atomic Energy Research Institute.The proton radiation of bipolar transistor is studied by means of the space environment simulation equipment of the key Laboratory of National Defense Science and Technology of Harbin University of Technology in terms of the behavior and evaluation technology of space environment materials.1.The Single Event Latch-up(SEL)effect and the characteristics of SEL maintenance current in HI-13 electrostatic tandem accelerator(HI-13)are studied with a low-voltage differential voltage regulator(Low Dropout Regulator,LDO)as an object of study.Under the irradiation of heavy ions Cl and Ge,the output current increases instantly,and the SEL effect is monitored successfully in the experiment.This LDO adopts two-ways power supply.For 1.8V input,the SEL current is between 850 mA and 950 mA when SEL occurs.For 3.3V input,the SEL current between 6.2 mA and 6.4 mA increases with the increase of current limit value,and the time of exiting SEL increases gradually until it is unable to exit.By analyzing the exit time of the SEL under different current limiting values,the maintenance current of the device SEL is between 350 mA and 400 mA.2.Taking a bipolar transistor abroad as the research object,the low energy proton with energy of 170 KeV was chosen as the irradiation source,and the displacement effect was studied by changing the flux of the radiation source and simulating the calculation and analysis.The characteristics of ionization effect and its synergetic effect and its influence on the degradation of electrical properties.The mechanism of the influence of different magnitude of flux on electrode and base current of bipolar transistor is analyzed.The relationship between collector current and base-emitter voltage is discussed by testing Gummel curve.The relationship between transistor current gain and radiation flux of low energy protons is studied emphatically.The output noise amplitude before and after irradiation is obtained by using 1/f noise testing equipment and the output noise amplitude is worth changing.The results show that the effect of displacement damage caused by the positive low energy proton irradiation of bipolar transistor leads to the degradation of the electrical properties of the device,but the ionization effect is not obvious in this experiment.The current gain of the bipolar transistor decreases with the increase of the flux,and the noise radiation of the device output decreases obviously after low energy proton irradiation.