Research Of The Fast Recovery Diodes

In this dissertation, the theory of fast recovery diode is expatiated, the reverserecovery time,forward voltage drop, reverse breakdown voltage and the relationshipsbetween them and the design are researched and explored..parameters and test princleare introduced indetail and the structure of the fast recovery diode inside and outside arecontrasted herein.According to the design principle and the train of thought of before, in order topresent my company is development and production of a certain type of glass passivatedfast recovery rectifier diode package as an example, the high power fast recovery diodestructure design and manufacturing technology is analyzed, combining with thepractical production test, to determine the reasonable structure parameter andtechnological process, development with small volume, current work, high reversevoltage, reverse recovery time, high reliability products.The subject process scheme selection of suitable resistivity and thickness of the Ntype silicon wafer, the extension and diffusion combining, precise control of base widthof the formation of P⁺NN⁺structure and thickness and adopting a method ofcombination of epitaxy and diffusion, diffusing with platinum diffusion source toshorten the life of minority carrier, consequently shorten the reverse recovery time.Matalizing by double-side evaporating, heightening reverse breakdown voltage by sandblasting mechanical shape and chemical corrosion to form mesa and protecting PNjunction by glass passivating to reduce surface pollution to lower surface leakagecurrent and heighten withstand voltage. Finally, get an ideal result of reverse breakdownvoltage（VBR）, forward voltage（VF） and reverse recovery time（trr）. The issue made out ofglass encapsulated passive entities like tube to the reverse breakdown voltage （VBR）（IR=100μA） at1200V or more, forward voltage （V_F）(I_FM=15A) drop reached1.4V or less,the reverse Recovery Time (t_rr)（I_F=0.5A, I_R=1A, IREC=0.25A） at the level of lessthan150ns.It will be a reference on products development and development thoughtsfor designers.