Influence of Backside p-Region Width on the Overcurrent Reverse Recovery of High-voltage RFC Diodes

Based on 2D device simulation, this paper reveals the influence of the backside p-region width on the overcurrent reverse recovery of high-voltage relaxed field of cathode (RFC) diodes. Through the study of 3.3kV diodes with different backside p-region width, it is found that the width affects the maximum transient lattice temperature. The most likely mode of destruction is local heating caused by a large number of small current filaments converging into strong current filaments. The smaller the width of the backside p-region, the more easily a large number of small current filaments gather together to form an uneven distribution of strong current filaments. When the optimum value Wp-region = 100 mm, the overcurrent ruggedness of the device is fully improved.