Semiconductor device with an insulating structure for insulating an electrode from a semiconductor body

A semiconductor device, comprising:

• a semiconductor body having a main surface with a normal direction defining a vertical direction, the semiconductor body comprising in a vertical cross-section:
• a first contact region of a first conductivity type which extends to the main surface;
• a body region of a second conductivity type which adjoins the first contact region and extends to the main surface;
• a drift region of the first conductivity type which adjoins the body region and extends to the main surface;
• and
• a second contact region which comprises a higher maximum doping concentration than the drift region and extends to the main surface;
• an electrode arranged on the main surface;
• and
• an insulating structure which insulates the electrode from the semiconductor body and comprises in the vertical cross-section:
• a gate dielectric portion which forms a first horizontal interface at least with the drift region and has a first maximum vertical extension between the first horizontal interface and the electrode;
• and
• a field dielectric portion which forms with the drift region a second horizontal interface, a third horizontal interface and a fourth horizontal interface, wherein the second horizontal interface, the third horizontal interface and the fourth horizontal interface are, in the vertical direction, arranged below the main surface, wherein the third horizontal interface is arranged between the second horizontal interface and the fourth horizontal interface, wherein a second maximum vertical extension of the field dielectric portion between the second horizontal interface and the electrode is larger than the first maximum vertical extension, wherein a third maximum vertical extension of the field dielectric portion between the third horizontal interface and the electrode is larger than the second maximum vertical extension, and wherein the electrode only partially overlaps the third horizontal interface.