Research And Improvement On Radiation-Resistance Characteristics Of Static Induction Transistors

With the development of aerospace engineering, radiation-resitant power semiconductor devices of high reliability, long life and space-level radiation become better the precondition of the development of aerospace engineering. Because of its unique structure, buried gate type static induction transistors(SIT) of the strong radiation-resitant characteristics has been widely used in the field of aerospace, satellites, spacecraft, ICBMs and so on.The radiation-resitant characteristics of static induction transistors was deeply studied in this dissertation based on the national natural science fund project(No:61366006): "Improvement on Source Breakdown Voltage and Key Technology Research of Static Induction Transistors", including the theory, technology, radiation effect on the device and experiments.Firstly, the basic structure of the static induction transistors, the current mechanism and the photoelectric effect during the irradiation were analysed theoretically. On this basis, it was determined theoretically that buried gate type static induction transistors of the excellent radiation-resitant characteristics as the device structure of this dissertation.Secondly, the layout and fabrication of the device were designed. First of all, in order to achieve the best radiation-resitant characteristics in the process, the optimum parameters were selected between the material parameters, structural parameters and technological parameters. The second thing was that the layers of layout of buried gate type static induction transistors were designed by L-Edit software. The last thing was that the specific technology processes of the device were studied. Based on the above three points, buried gate type static induction transistors of the excellent radiation-resitant characteristics were come true in the process.Thirdly, the impact of radiation on the SIT was deeply studied. Through the study of the radiation environment and the radiation effect, the Co60-? ray was chosen as a source of radiation. And through analyzing the current before and after radiation, the I-V characteristics before and after radiation of the static induction transistors and some distribution changes of the electronic potential along the channel center line were simulated by an Atlas module of the Silvaco Tcad software. On the basis of the above, the effect of radiation on static induction transistors was obtained theoretically.Finally, the characteristics of SIT before and after radiation were tested and analysed. In radiation theory, on the one hand, the total dose radiation experiments were carried out to the static induction transistors 2SK182 E. On the other hand, some test experiments were carried out, including the I-V characteristics, the gate-source breakdown characteristics and the frequency characteristics before and after radiation. On the basis of the above experiments, the radiation effect on the electrical properties of the static induction transistors was analysed comparatively. All of these working parts make a real contribution to obtain a static induction transistor of the strong radiation-resitant.