A semiconductor drift device, comprising: - a substrate of semiconductor material, - a deep well of a first type of electrical conductivity provided for a drift region in the substrate, - a drain region of the first type of electrical conductivity arranged at a surface of the substrate at a centre of the deep well of the first type, - a plurality of source regions of the first type of electrical conductivity arranged outside the deep well of the first type, and - a single deep well or a plurality of deep wells of a second type of electrical conductivity opposite to the first type of electrical conductivity provided for a plurality of gate regions at the periphery of the deep well of the first type so as to define a boundary therewith; wherein - the source regions are arranged in shallow wells of the first type of electrical conductivity at the periphery of the deep well of the first type, - the shallow wells of the first type extend into the deep well of the first type so as to exceed said boundary by a positive first distance; - the gate regions are formed by shallow wells of the second type of electrical conductivity, which are arranged at the periphery of the deep well of the first type, the gate regions being arranged in the single deep well of the second type or each in a corresponding one of the plurality of deep wells of the second type, the shallow well of the second type and the shallow wells of the first type being alternately arranged at the periphery of the deep well of the first type, the shallow wells of the first type occupying the regions between adjacent shallow wells of the second type, and, - in case of a single deep well of the second type, the single deep well of the second type extends continuously under the shallow wells of the first type or, - in case of a plurality of deep wells of a second type, gaps are present between adjacent deep wells of the second type, the shallow wells of the first type are arranged above the gaps and a first dimension of the shallow wells of the first type, which is defined by a distance between two adjacent shallow wells of the second type, is larger than a second dimension of the gaps, which is defined by a distance between two adjacent deep wells of the second type. - a substrate of semiconductor material, - a deep well of a first type of electrical conductivity provided for a drift region in the substrate, - a drain region of the first type of electrical conductivity arranged at a surface of the substrate at a centre of the deep well of the first type, - a plurality of source regions of the first type of electrical conductivity arranged outside the deep well of the first type, and - a single deep well or a plurality of deep wells of a second type of electrical conductivity opposite to the first type of electrical conductivity provided for a plurality of gate regions at the periphery of the deep well of the first type so as to define a boundary therewith; - the source regions are arranged in shallow wells of the first type of electrical conductivity at the periphery of the deep well of the first type, - the shallow wells of the first type extend into the deep well of the first type so as to exceed said boundary by a positive first distance; - the gate regions are formed by shallow wells of the second type of electrical conductivity, which are arranged at the periphery of the deep well of the first type, the gate regions being arranged in the single deep well of the second type or each in a corresponding one of the plurality of deep wells of the second type, the shallow well of the second type and the shallow wells of the first type being alternately arranged at the periphery of the deep well of the first type, the shallow wells of the first type occupying the regions between adjacent shallow wells of the second type, and, - in case of a single deep well of the second type, the single deep well of the second type extends continuously under the shallow wells of the first type or, - in case of a plurality of deep wells of a second type, gaps are present between adjacent deep wells of the second type, the shallow wells of the first type are arranged above the gaps and a first dimension of the shallow wells of the first type, which is defined by a distance between two adjacent shallow wells of the second type, is larger than a second dimension of the gaps, which is defined by a distance between two adjacent deep wells of the second type.