Characteristic Optimization Design Of 2500V/2A Fast Recovery Diode

2500V/2A fast recovery diode with low turn-on voltage, short switching time, small size(diameter only 3mm) and other advantages, have a wide and important application in the aerospace and military fields. The causes and mitigation mechanism of LC oscillation are studied by analyzing the factors that affect the static and dynamic characteristics of the diode.The main factors influencing the dynamic avalanche tolerance are discussed, and the final optimized structure parameters of the i region, buffer layer, anode region and terminal are obtained. The main research contents and results are as follows:(1) The influence of the structural parameters of the cathode side buffer layer and the P region on the reverse recovery characteristics of the 2500V/2A fast recovery diode are analyzed.With the reduction of the concentration in the P region , the lifetime of the minority carrier and the concentration gradient of the buffer layer, the reverse recovery time of the diode decrease a lot.(2) The reason for the LC oscillation of the 2500V/2A fast recovery diode at the end of the reverse recovery and the suppression of the LC oscillation b innroduccng of the cathode buffer layer structure are investigated, The results show that the introduced buffer layer structure avoids the pn junction and nn+ junction of the electric field through , eliminating the oscillation phenomenon.(3) The influence of the doping concentration of P region and the structure of cathode buffer layer on the dynamic avalanche tolerance of 2500V/2A fast recovery diode was studied and optimized. The results shovw that the peak intensity of the electric field at the diode nn+junction decreases from 2.1 × 105V/cm to 1×104V/cm, and the avalanche tolerance is improved.(4) According to the above conclusions, the main structural parameters of the diode such as i region, p region, buffer and beveled terminals , are determined by simulation. The optimized parameters of the diode are trr =100ns, VF=2,3V, Irm=14A, achieved the design indexes.The research results of this subject have the guidance and reference value for the research of small volume high voltage diode.