Neon implantation and the radiation enhanced diffusion of platinum for the local lifetime control in high-power silicon diodes

Abstract

About 10 MeV helium and 120 MeV neon implantations were used for the local lifetime control of silicon power diodes with subsequent annealing at 200 °C. DLTS measurements show that the concentration ratio between VO (–/0) pairs and divacancies V 2 ( – / 0 ) after the implantation of neon is close to one in agreement with the data published for other heavy ions. The implantation dose to achieve the same point at the technology curve of the diodes under test was found about 10 times lower for the neon compared to helium. The radiation enhanced diffusion (RED) of platinum at 725 °C was evaluated both for the enhancement by implantation of helium and neon. The electrical parameters of silicon diodes (carrier lifetime, voltage drop, leakage current and reverse recovery) were compared. One order lower implantation dose of the neon compared to that of the helium was found necessary to obtain the same improvement of electrical parameters. The RED of Pt using the neon implantation was found functional in a similar way to that of the helium. The reduction of carrier lifetime, which would be normally sufficient for robust diodes, was found for the doses of neon at about 1 × 10 13 cm −2. However, the simultaneous increase of background doping concentration at the end of range of neon, which increases electric field, was found responsible for the decreased static breakdown voltage, decreased turn-off ruggedness and increased leakage current.