A novel high-voltage sustainings structure with buride oppositely doped regions is dermonstrated. Due to the resistivity andior the thickness of the voltage-sustaing layer can be made smalier than that of a conventional one with the same breakdown voltage, and therefore the on-resistance (of unipolar cnductionl can the re-duced. The theory developed for designing such structures is found to be in good agreement with the results obtained from two-dimen-sional (2D)simulation as well as from experiment. A 500 V VD-MOST using such a structure as the drift region and with proper edge termination is fabricated. Results show that its on-resistance is lower than value given by the conventional "sillcun limil"