Semiconductor devices and method for manufacturing semiconductor devices

A power semiconductor device, comprising:

• a semiconductor substrate having a drift region;
• a gate electrode trench in the semiconductor substrate, extending into the drift region and comprising a gate electrode arranged in the gate electrode trench and electrically insulated from the drift region by a gate dielectric layer arranged between the gate electrode and the drift region;
• and
• a field electrode needle trench in the semiconductor substrate, laterally spaced from the gate electrode trench and extending into the drift region, the field electrode needle trench comprising a field electrode arranged in the field electrode needle trench and electrically insulated from the drift region by a cavity formed in the field electrode needle trench between the field electrode and the drift region.

A power semiconductor device, comprising:

• a semiconductor substrate having a drift region and a body region;
• a field electrode needle trench in the semiconductor substrate extending into the drift region, the field electrode needle trench comprising a field electrode arranged in the field electrode needle trench and electrically insulated from the drift region by a cavity formed between the field electrode and the drift region;
• an electrically conductive plug arranged in an upper portion of the field electrode needle trench and partially closing the cavity on a laterally first side, the electrically conductive plug being in electrical contact with the body region;
• and
• an auxiliary plug arranged in an upper portion of the field electrode needle trench and closing the cavity on a laterally second side,
• wherein the electrically conductive plug and the auxiliary plug together completely close the cavity.