Connection, configuration, and production of a buried semiconductor layer

A power transistor having a semiconductor volume comprising:

• a plurality of transistor cells connected in parallel and isolated from one another by trenches;
• a laterally oriented, highly conductive semiconductor layer buried below the transistor cells in the semiconductor volume;
• and
• means for contact-connecting the buried semiconductor layer from the top side of the power transistor;
• wherein at least one trench reaches into the buried semiconductor layer, the trench bottom of the at least one trench being lined with a highly conductive layer.

A method for producing a power transistor comprising:

• providing a plurality of transistor cells connected in parallel;
• burying a laterally oriented, highly conductive semiconductor layer below the transistor cells in a semiconductor volume;
• and
• forming a connection, via which the buried semiconductor layer can be contact-connected from a top side of the power transistor, in a trench extending from the top side of the power transistor toward the buried semiconductor layer;
• wherein the buried semiconductor layer are produced by:
• forming a plurality of trenches in the semiconductor volume;
• and
• applying dopants to the surface of the semiconductor volume in such a way that dopants enter into the semiconductor volume through the inner walls in the lower region of the trenches.