Research Of The Effect Of Electron Irradiation Conditions On The Defect Energy Levels And Performance Of N-Si Diode

With the deep research on various kinds of radiation rays and their irradiation effects,irradiation technology has been used in semiconductor materials,device modification and other fields.As the one of the main life control technologies,because electron irradiation technology has characteristics of good consistency,simple process,low cost,has been applied to improve the performance of semiconductor device.But at the same time to improve the switching speed of the device,it will also affect other electrical properties.The variation of the device performance is related to the defect energy level introduced in the semiconductor material by irradiation.In this paper,we studied the effect of different electron irradiation conditions on the performance of the diode,the main work was as follows:?1?We used an electron beam with four different energies?0.5,1.5,2.0,and 5.0MeV?to irradiate n-Si diodes,the minority carrier lifetime?,deep level transient spectroscopy?DLTS?,and positive and negative output characteristic curve were measured before and after irradiation with different irradiation fluence levels,the forward voltage drop V_F,reverse leakage current I_R,reverse recovery time t_rr were recorded as sensitive parameters,and the effects of electron irradiation conditions on the performance of the diodes were compared and analyzed.?2?The results showed that the experiment introduced a maximum of eight defect energy levels in the packaged n-Si diodes with different electron irradiation conditions,which included four majority carrier defect energy levels and four minority carrier defect energy levels.These defect energy levels can act as recombination centers reduced the minority carrier lifetime?,and with the increased of irradiation energy,the minority carrier lifetime speeded up the pace of decline.The defect energy level may appear and disappear,the concentration of the levels may increase,decrease or remain unchanged,the energy level positions varied within a range under different electron irradiation conditions,the reasons for these changes are related to the stability of the irradiation defects and the compensation and superposition of the energy levels.?3?The forward characteristics of samples before and after irradiation degraded,the forward voltage drop V_F increased,and showed a linear relationship with the irradiation fluence?_n.When irradiation was excessive,the positive output characteristic curve was distorted.The reverse characteristic of samples degraded when the irradiation energy was 2.0 and 5.0MeV.The reverse leakage current I_R increased,and showed a linear relationship with the irradiation fluence?_n when irradiation energy was 5.0MeV.Compared with the forward characteristics,the degradation of the reverse characteristics were more unstable,only part of the samples degenerated under the same irradiation conditions,and the reverse output characteristic curve of some samples was distorted.The reverse recovery time t_rrr decreased when the irradiation energy was 2.0 and 5.0MeV,consistent with the results of minority carrier lifetime experiment.