Electronic device including a drift region

An electronic device comprising a transistor structure, wherein the transistor structure comprises:

• a buried conductive region having a first conductivity type;
• a semiconductor layer overlying the buried conductive region, the semiconductor layer having a primary surface and a second conductivity type opposite the first conductivity type;
• a drift region adjacent to the primary surface;
• a sinker region contacting the drift region and extending deeper into the semiconductor layer as compared to the drift region;
• a drain contact region spaced apart from the drift region;
• a resurf region having the second conductivity type, wherein the resurf region is spaced apart from the primary surface, is spaced apart from the buried conductive region by a portion of the semiconductor layer, and extends under the drift region, wherein, within the transistor structure, none of the resurf region contacts the buried conductive region;
• and
• a first trench isolation structure that extends from the primary surface to a depth in a range of 0.2 micron to 0.9 micron, wherein the first trench isolation structure overlies the resurf region.