| In the application of new power electronic devices, a paralleled fast recovery diode is required for free-wheeling. With the wide application of IGBT power modules, the higher requirements for electrical characteristics and reliability of the paralleled free-wheeling diode is put forward. The diode is not only required with high voltage, large current and low loss, but also the higher softness, higer surge-current capability and the higher avalanche ruggedness.A new high voltage fast recovery diode (FRD) structure with an IDEE anode and a FCE cathode is presented. The operating mechanisms, static and dynamic characteristics are studied by Sentaurus-TCAD. Finally, the key parameters are optimized. The main contents are as follows:Firstly, the structural features of IDEE-FCE FRD are analyzed, operating mechanisms of IDEE-FCE FRD are studied, and hole injection efficiencies of diodes with different anodes and cathodes are comparely analyzed. Compared with the common anode structure, the hole injection efficiency is inverse at high current density level when the IDEE anode structure is adopted, which makes a trade-off between surge-current capability and reverse recovery peak current. Compared with the common cathode structure, the diode with the FCE cathode structure can obviously improve the reverse recovery characteristic and avalanche ruggedness.Secondly, static and dynamic characteristics of IDEE-FCE FRD are studied. Compared with common pn nn+, IDEE and FCE diodes, IDEE-FCE FRD has the better trade-off among the forward conduction, reverse recovery, the surge-current capability and the avalanche ruggedness.Thirdly, the key structure parameters, such as doping concentration and width of IDEE anode p+ area, width ratio of FCE cathode p+ area, doping concentration and thickness of buffer layer, of IDEE-FCE FRD are optimized. The influences of the key parameters on FRD characteristics are analyzed and the key parameters values are determined.The research results in this paper have a certain reference value for the design and development of fast recovery diode. |
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