Thesemiconductor drift devicecomprises a deep well of a first type of electrical conductivity (1) provided for a drift region in asubstrateof semiconductor material, a drain region (6) of the first type of conductivity at the surface of the substrate, a plurality of source regions (5) of the first type of conductivity in shallow wells of the first type of conductivity (3) at the periphery of the deep well of the first type(1), and a deep well or a plurality of deep wells of an oppositesecond type of electrical conductivity (2) provided for a plurality of gate regions at the periphery of the deep well of the first type(1). The gate regions are formed by shallow wells of the second type of electrical conductivity(4), which are arranged in the deep well of the second type (2) between the shallow wells of the first type(3). Significant figure: Figure