HIGH-VOLTAGE SUPER-JUNCTION SOI-LDMOSFETS WITH REDUCED DRIFT LENGTH

摘要

We describe high-voltage super-junction SOI-LDMOSFETs which have a trench oxide in the drift region. The super-junction helps to increase the effective drift doping. The trench oxide in the drift region allows to reduce the drift length without degrading the breakdown voltage. With the proposed device structure a reduction of the on-resistance of the n-drift layer can be achieved. The breakdown voltage and the specific on-resistance of the suggested devices as a function of the trench oxide depth, the p-column width, and the doping are studied. Using the two-dimensional numerical simulator MINIMOS-NT, we confirm that the specific on-resistance of the device proposed is lower than that of conventional SOI-LDMOSFETs, and the drift length is reduced to 65% compared to conventional devices.