On the influence of recombination centers on the electrical performance of silicon power rectifiers

Silicon ultrafast recovery diode with leakage current reduced via the combined lifetime process of gold diffusion and electron-beam irradiation

“…Figure 7(a) shows the relationship between the leakage current and trap density ratio (N EI /N Au ) for the combined-processed diodes, in which only the irradiation dose increases from 1200 to 3000 kGy as the switching time decreases while the diffusion temperature of Au remains fixed at 935 • C. For the solely Au-diffused diode, diffusion temperature of Au increases from 970 to 1000 • C as the switching time decreases. The trap density ratio was calculated using the trap density for E c -0.39 eV (N EI ) at the acceptor level [49], which was the defect level formed via electron beam irradiation, and that for E c -0.51 eV (N Au ) at the acceptor level [9], which was the level of diffused Au observed via DLTS (figure 5). Calculations were performed using (N EI /N Au ).…”

“…Figure 9 shows the recombination model of carriers generated in the depletion layer for the combined-processed diode. The trap level of diffused Au (E c -0.51 eV) is the acceptor level [9], and the trap level of defects (E c -0.39 eV) caused by EI is the acceptor level [49]. For the trap level of diffused Au (E c -0.51 eV), electrons and holes recombine with a high probability because an electron captured from the conduction band remains at the deep trap level for an extended period [59].…”

“…Therefore, the leakage current needs to be reduced. The diffusion of Au to Si, which controls the lifetime of minority carriers is the method to reduce the switching time [9][10][11][12][13][14][15][16]. In the recent study, the process to improve switching performance by controlling the uniformity of the metal concentration is investigated [17].…”