Analysis of direct wafer bond IGBTs with heavily doped N+ buffer layer

High-speed IGBTs fabricated using direct wafer bonding and implanted N+ buffer layer are described and analyzed in this paper. The trade-off between on-state voltage drop and turn-off fall time can be controlled by varying the N+ implant dose prior to the wafer bonding process. 800 V IGBTs with switching time less than 100 nanoseconds and V/sub ce(sat)/ as low as 1.4 V at 100 A/cm/sup 2/ have been obtained. This excellent performance is achieved without utilizing any conventional lifetime control techniques.