Integral diodes in lateral DI power devices

The performance of integral diodes of DI LDMOSFETs and collector shorted (CS)-LIGBTs is compared to the LPiN diode. The integral diodes of the LDMOSFETs and CS-LIGBTs were found to have on state voltage drops comparable to the LPiN diode because of their lower operating current densities. Simulations indicated reduced stored charge for the integral diodes compared to the LPiN diode. Measurements showed superior reverse recovery characteristics for the integral diodes compared to the LPiN diode. However, parasitic bipolar turnon was observed in the integral diodes when operated at large current densities. Considerable improvement in the reverse recovery characteristics was observed for all the three cases with reduction in drift region thickness, at the expense of an increase in the forward voltage drop. The results of this study allow the conclusion that the integral diodes provide superior performance when compared with a separate LPiN diode, allowing substantial savings in chip area.