Reverse recovery of Si/Si1 − x Ge x heterodiodes fabricated by direct bonding

Abstract

633 Important elements in the schemes of electric energy converters created on the basis of modern semiconductor switches (bipolar fieldeffect transis� tors or gated thyristors) are highpower, fast response highvoltage diodes that are connected counterparal� lel to the switch and operate under severe conditions of rapidly switching highpower signals with high rates of reverse current buildup. These diodes must combine a small direct voltage drop in the switchon state with fast and "soft" recovery of the blocking ability. This combination can be achieved by creating a certain dis� tribution profile of the electron-hole plasma accumu� lated during the direct current passage in the diode base, such that the plasma density in a narrow region at the pn junction is significantly lower that in the other parts of the base. One possible solution of this task consists in increasing the concentration of recombination centers (so as to reduce the minority carrier lifetime in this region of the base), using the irradiation by protons or α particles with energies ensuring a sufficiently high concentration of radia� tioninduced defects (1). However, the necessity of using α particle (or proton) accelerators with ener� gies up to ~10-15 MeV makes this technology of fastrecovery highpower diodes very laborious and energyconsuming. This Letter considers the possibility of creating highvoltage fast recovery diodes based on of