Semiconductor Device with First and Second Field Electrode Structures

A semiconductor device, comprising:

• first field electrode structures extending from a first surface into a semiconductor portion, the first field electrode structures comprising a first field dielectric insulating first spicular field electrodes against the semiconductor portion, and
• second field electrode structures extending from the first surface into the semiconductor portion, the second field electrode structure comprising a second field dielectric, which is thicker than the first field dielectric and which insulates second spicular field electrodes against the semiconductor portion, wherein
• openings of the second field electrode structures and openings of the first field electrode structures in the first surface are non-circular symmetric and the openings of the second field electrode structures are greater than the openings of the first field electrode structures.

A semiconductor device, comprising:

• first field electrode structures extending from a first surface into a semiconductor portion, the first field electrode structures comprising a first field dielectric insulating first spicular field electrodes against the semiconductor portion, and
• second field electrode structures extending from the first surface into the semiconductor portion, the second field electrode structure comprising a second field dielectric, which is thicker than the first field dielectric and which insulates second spicular field electrodes against the semiconductor portion, wherein
• openings of the second field electrode structures in the first surface have a same shape as and are greater than openings of the first field electrode structures, and both the first and the second field electrode structures are in a transistor cell area comprising transistor cells configured to control a current flow through the semiconductor portion.

A method of manufacturing a semiconductor device, the method comprising:

• forming, contemporaneously, first and second trenches extending from a process surface into a semiconductor layer, wherein a first horizontal dimension of the trenches does not exceed more than 5 times a second horizontal dimension orthogonal to the first horizontal direction;
• and
• heating the semiconductor layer to form a dielectric layer comprising first layer portions lining the first trenches and second layer portions lining the second trenches, wherein the second layer portions are formed thicker than the first layer portions.