Carrier lifetime control optimization for high speed IGBT based on electrical and physical analysis

It is well know for IGBT to utilize an Electron Beam (EB) irradiation and a post thermal annealing process as a carrier lifetime control for a thick n-drift layer. The stability of the electrical characteristic such as the ON state forward voltage drop Von as V_CE(sat) and a turn-off loss (Eoff) is required from the viewpoint of reliability for both an economical small chip size in a high current density operation and a shortened carrier lifetime to reduce an Eoff in a high speed operation. In this paper, we report the complex combination effects of carrier lifetime control processes and a DC current stress, which simulated an entire lifetime of device usage under high current density conduction, by both the IGBT´s electrical characteristics stability and a physical analysis using the Cathode Luminescence (CL) method.